Best 20 G hull

[William Davis]

Looking for the best 20 G hull for my two Trojans. Only junk euro hulls available picked up from bins around here. Bought a flat of 20 g STS used them in my 870 then loaded with 3/4 oz 20/28 and Winchester 209s.

High primers giving me trouble. One Trojan well worn closes nice on the shells. Other, almost unfired gun closes tight at times on the same shell. It’s the primer causing trouble. Figured I would go ahead and pay the Haz and shipping fees & get some Remington primers. Comes out to nearly 80 dollars a thousand

Is a flat of AA 20s and staying all Winchester the answer ? My grandson would make quick work of the AAs in the 870.

William

[Rich Anderson]

Are you looking for 2 3/4 inch hulls? Do you want to reload them? I have used Chedditte hulls with great success but I have gone to 2 1/2 inch hulls and use the RST hull. When I shot registered skeet the AA or STS hulls worked fine. Make sure you getting the primer fully seated in the hull. I have had some difficulty when using a Rem primer in a AA hull esp in 28ga.

[Richard Flanders]

The high primer issue in the STS hull is indeed an issue between the nose profile on Remington primers being radiused and other primers which are not. When Remington fits the base to their hull they somehow use heat which generates a large melted plastic burr at the end of primer hole that pushes any non-radiussed primer(WW) back out a bit, which is, as you have learned, is very aggravating. You can remediate the issue by taking a General brand tapered reamer and removing some of the burr on every hull. Been there on this one, especially, I think on STS 28ga hulls. Get rid of that burr and the issue is solved, but it's a time-consuming project. I do think that, in general and with the exception of the older and heavier WinAA hulls, the STS are the best small gauge hulls, though, so I have actually reamed a large batch of mine. The newer Win AA 20ga hulls generally last no more than 2 reloads for me, and often not even the original firing, before splitting at the mouth.

[William Davis]

2 3/4 is fine with me. I use Cheddites in my 16 g loads out of necessity, if I can avoid them for other gauges so much the better.

I might try that ream the primer pocket trick on the STS hulls I have on hand. If the AA hulls only go a few loads before splitting would be hard to keep up with demand using a pump to empty factory shells. I don’t like factory 20 G shells in my SXS guns. Safe but not pleasant.

Let you guys know how it worked out

William

[Richard Flanders]

It definitely works. Some you can ream from the back end, others need some reaming from the mouth end. Seems I remember that I did most of mine from the mouth end. The General reamers are readily available from many box and hardware stores.

[William Davis]

Boy you guys showed me something !

I went to my pin punch set. Found one that mikes .2315. It goes in AA primer pockets from the breech end nice fit, and all the way through to the inside of the hull. STS and a old Remington Peters “skeet” goes in the pocket and stops short. Shorter than a primer.

Put a tapered hand reamer in the two Remington hulls from the mouth few twist and the pin punch slides in same fit as the AA hull.

Going to make a 50 shell run ream and load, see if it’s a cure.

William

[Ken Hill]

I like the Rem STS hull and never had a problem with the win209 primers.

The new AA shells will sometimes buckle during reloading; even the once fired shells. I also had them split after firing so I stayed with the Rem STS hulls.

Since you are using hulls after being fired in a different gun, are you resizing the hulls during reloading?

Ken

[Richard Flanders]

Glad to help William. It's definitely a cure if you make sure to ream enough of the plastic burr out.

[Gary Laudermilch]

I have loaded many thousands of STS 20's with Win 209 primers and never had a problem. The problem is getting the hulls. They are like gold. I have been experimenting with the new Rem Clay/Field hulls. I have run some through 7 reloads and they held up well. Certainly a viable alternative to STS hulls.

[Richard Flanders]

My encounter with this issue was primarily with 28ga STS hulls. I assure you, though, that William is not making this up. If his primers backed out, he has the same issue with his 20ga hulls. His experimenting with a reamer is proof of concept for the cure.

[Craig Larter]

I have used both STS and Gun Clubs in 20ga 3/4oz Clay Buster wad with chedditte primers. I much prefer the gun club to STS, I get much better crimps. The STS hulls are thicker at the mouth which causes a slight mushroom at the mouth making it necessary to push the shell into the chamber of my Fox, I don't have this issue with the Gun Clubs with the same MEC 9000 press. Also make sure your resizing to suit your chamber---Foxes are normally tight.

[William Davis]

Running them in a Ponsness Warren 375 sizes the whole case. Shell drops in the chamber fine. The Trojan with light use gets the occasional hard to close. Well worn Trojan never happened . Took me a while to figure it out. Even stripped the gun and polished the cocking slide thinking it was a gun issue . it was hard to open too.

Finally painted dozen loaded shells heads with layout die. Scrapes on the hard to opens were on the primers . Friend of mine has same interment issue with Remington Gun Clubs in a Beretta 687.

If I pay attention to pushing the press operating handle real hard no high primers. But something was hanging up when seating for sure.

William

[Chuck Bishop]

Craig, the last station on your 9000 should taper the mouth of the shell. Do you use it?

[Craig Larter]

Yes I do Chuck. But before I get a good taper it crushes the sts hull. No issue with the gun clubs with exactly the same press settings. I was so frustrated with the sts hulls I called mec technical support. They offered no suggestions. Maybe the design of the 3/4oz wad???

[Gary Laudermilch]

Craig, years ago I loaded a ton of Gun Clubs and then they began to vary in overall length which caused erratic crimps so I switched to STSs. When first loading the STS I encountered the problem you describe. The solution was to adjust the press. I increased the crimp starter a wee bit, adjusted the crimp die to put less pressure on the outside but a bit more on the center punch, and slightly increased the finishing die. Problem solved and I have shot these shells in 7 different 20's with no discernable difference in any of them.

As an aside, last year I loaded some new gun clubs with 3/4 oz loads so I could easily tell them apart from 7/8 oz loads. The plastic on the newer gun clubs was so stiff that the press handle pressure was so excessive I gave up after a few hundred rounds. Then I tried the Field/Clay hulls and found them to be nearly identical to the STS in crimp quality, longevity, and interior volume. I've loaded quite a few 3/4 oz loads with the CB1075-20 wad and they work beautifully. No press adjustments required.

[Rich Anderson]

I'm no fan of the STS 28ga hull. The end frosts after firing and case life is crap. For me the old AA hull is superior and fortunately I have lots of them. Using the correct new HS wad helps in that hull and IMHO it 's a better hull than the STS.

[Craig Larter]

Gary thanks so much for the tip I will give it a try.Craig Larter

[Paul Harm]

Many guys may not have a tapered reamer. Just select a drill bit that goes in the primer hole, around 15/64, and you can cut the plastic out. I did it about 10 years ago on 28ga and it worked great. I've never had the problem with 20 or 12ga Remingtons.

[William Davis]

Just finished 50 it’s quick work with a reamer. I used a pin gage to check & make sure I did not over open. Load them tomorrow & test them in my Trojan

Will see

William

[David Lien]

Have any of you 20 Ga. Reloader's tried the Remington Hull with the yellow Plastic base wad?? I did load up some of these hulls couple of weeks ago and they did what I wanted done. ((Field Loads)) I found that the Federal wad is larger in diameter than some of the other wads, and worked well. The loads shot very well, clean burning and good velocity. I most likely load at higher pressures than some of you, but the hulls held up good. No Primer issues, Crimps were 6 point, and I loaded them four or five times working up a load. I think I may like these hulls. Just a thought :) David

[Bill Murphy]

Gun Clubs delivered to my club at less than $5.00 a box means that my 20 gauge 800B has been put aside for a few years. The hulls are great to load, but no one will take them, even for free. Gun Clubs and other $5.00 12 gauge shells are all anyone uses around here any more. Since I moved in July, I have been selling and giving away components, even lead. My shooting buddy built my new gun room hardware and was paid off in components.

[Craig Larter]

Bill your saying you can buy 20ga gun clubs for less than $5.00 per box? Wow that's cheap!!!

[Paul Harm]

Yes, but I can reload 7/8oz shells for 3.45/box. That's still a nice savings - 29,or round it off to a 30% savings. I'll keep reloading.

[Rich Anderson]

If your looking for an inexpensive factory load consider the Italian company Clever. I have been using these in both 12 & 20 for about $6/box. The 3/4 oz 20 is a joy to shoot. Easy on the recoil and murder on targets.

[Tom Flanigan]

I have loaded all of the cases mentioned with CCI primers and have not had any problems.

I have used CCI for years because they are a low pressure primer (CCI regular not magnum primers which are very hot). Federal primers are very hot and winchester less so but still hot. Remington primers are good and just a bit hotter than the CCI's. You can find load in the manuals that uses CCI primers, Remington wads and IMR 4756 for 12 bore 1 and 1 1/8 oz loads. Pressures will be under 7,000 psi and the loads are very comfortable to shoot.

[Paul Harm]

From everything I've read only the Fed209A and CCI209M are hot primers. Everything else is about the same with slight differences. Remington primers are usually considered the ones giving the least pressure. I use the Cheddite primer and if loading at low pressure, say under 7500psi, I don't worry which of the mild primers is used in a formula. The pressure won't change all that much. PB, 7625, and 4756 are all discontinued. It's too bad because many of us liked them. American Select, Promo, Red Dot, Green Dot, and E3 are some of the powders I've used for light low pressure loads. I'm sure there's many others.

[William Davis]

Further to the Remington hull primer pocket dimensions. I was measuring the STS vs AA pockets with a pin punch set. Picked one with a slip fit on the AA that goes all the way through. And entered the STS then stops short.

Yesterday turned a gauge that is a nice snug fit all the way through the AA hull. Pushed in the fresh de-primed STS it stops a measured .01O short = Ten Thou short. Reaming with a tapered hand reamer from the mouth opens the flash hole enough for the gauge to slip through snug fit. No doubt about it the Remington hulls primer pocket is different.

Have not loaded any of the reamed STS yet. When I do will measure primer depth carefully comparing to factory some of the reloaded STS that gave my tight Trojan trouble. And some of my AA reloads, see what that says. Real test is will they function.

William

[Paul Harm]

Man, I don't know. All you guys having trouble with the 12 and 20ga shells. Only the 28ga have given me any problems. For as long as I can remember primers have always gone in the 12 and 20 with no problems. Most of the guys at my club load Remington shells and have never complained about primer fit. They use either the Cheddite or Win primer. I tried a Rem Gun Club 12ga and there was plastic going over the end but I had already been reloading it a couple of times without problems. A 15/64 drill bit cleaned it out. If using a tapered hand reamer I'd always be worried about going in too far. With the drill, which is cheaper and easier to find, it's a no brainer - what I need. I just checked to see what size drill it took. Never in all my years of reloading have I had to fix anything but the 28ga Remingtons. My friends and I must have magic presses that push the primers in.

[William Davis]

Paul primers are a press fit. Successfully inserting a part pressed fit into another will vary according to parts size, how much pressure is applied and the material itself. Plastic will allow a larger variance in size than other materials . It’s my guess differences in result we see is due to the amount of pressure applied when seating the primer. Probably differences in the plastic itself and different guns have different high primer tolarance . Likely smaller the gauge more it shows.

I agree with you, tapered reamer may not be the best tool,considering how much needs to be removed. I plan to measure my reamer and see what the size differences are. Point of contact vs reamed. Easy to use a drill to do the same thing. Would take a very small cylindrical reamer but they are available. None in my toolbox.

None of this needed if I had not bought a 2nd 20 G Trojan or been able to match STS hulls with Remington primers. Rain the last few days time to experiment too.

William

[Tom Flanigan]

From everything I've read only the Fed209A and CCI209M are hot primers. Everything else is about the same with slight differences. Remington primers are usually considered the ones giving the least pressure. I use the Cheddite primer and if loading at low pressure, say under 7500psi, I don't worry which of the mild primers is used in a formula. The pressure won't change all that much. PB, 7625, and 4756 are all discontinued. It's too bad because many of us liked them. American Select, Promo, Red Dot, Green Dot, and E3 are some of the powders I've used for light low pressure loads. I'm sure there's many others.

Paul, if you look at the loading manuals and compare loads, you'll see that Winchester primers are relatively hot, especially when using compression formed AA hulls. You are right about IMR 4756 being no longer made. I used to buy a few 8 pound canisters at a time to get a discount and have about four pounds left.

With the CCI regular primers, my target 12 bore loads developed only 6,600 PSI with minimal recoil. I used the CCI primer to get under 7,000 PSI. I couldn't do that with any other primer except for Remington which is a tad higher pressure than the CCI.

For my taste, red dot has relatively high pressure and green dot less so. When my 4756 is gone, I'll go to 700X. I don't like American Select because I can't get the pressures where I want them.

I like to keep my 12 bore target loads under 7,000 psi. I shoot a ton of them through my Parkers and the lower recoil is easier on old wood.

[Paul Harm]

I don't buy Rem primers because of the cost - about $200/5000, where as Cheddites and CCI are 117/5000, Win are 130/5000, and Fed are 140/5000. Same for factory wads- about double the cost of ClayBusters. The CBer wads usually have lower pressures if that's what you're going for. With a CB 1100 wad, Win primer, 1oz of shot and American Select powder you get 1200fps at 6900psi. In my 2006 IMR manual they don't show 4756 for any 1 or 1 1/8oz load. With 7625 it doesn't matter what primer or wad - Win, Fed, or Rem, all loads are under 7000psi at 1200fps. I don't see a CCI primer reload in the IMR book. In the Alliant book they show just a couple of loads with CCI's and the pressures are the same as with Win primers. I load mostly 3/4 and some 7/8oz loads so the powders I listed were for them. I see with a 1 or 1 1/8oz load pressures are up a bit, but as long as they're under 8000psi I'm happy. If less recoil is what you're after, reduce the shot. Pressure is not in the recoil formula - velocity squared times the weight of shot, wad, and the powder is in the formula. I think if you do a little research you'll find CCI,Win, Rem, and Cheddite primers all have about the same pressures. I may buy CCI primers next time I order. Some shooters have complained about Cheddites piercing. And the CCIs are made in the USA.

[Tom Flanigan]

I use my old Lyman Handbook that was probably printed in the 90's or earlier. Lots of CCI primer loads in there. Listed in the Lyman manual is the Hogdon Powder Primer Variation test for the 1 1/8 oz. 12 bore load. All the other components are equal which is necessary to really compare pressure since many other factors can come into play. The CCI primer showed 8,400 psi, the Winchester at 10,900 psi and the Federal at 11,000 psi. Pretty high pressure for all. I’d like to know what the load consisted of but, other than the primers, it wasn’t mentioned. There are loads at 7,000 psi or under for all of these primers, but not in the 1 1/8 oz. load.

I’ve heard that pressure does not impact recoil but I remain unconvinced. My 12 bore, low pressure loads kick less than comparable Gun Club or AA loads. They are much more comfortable to shoot. It’s the same with every gauge even the 28. My 28 loads are much softer to shoot that any factory load. If pressure doesn’t have any impact on recoil, I’d like to know why my shells, compared to comparable factory shells, kick so much less. Maybe someone with a relevant degree can inform me. I’d like to know for sure.

I don’t load less than an ounce in the 12 bore. There isn’t any need to. I can get the pressures, recoil and performance I want with the 1 oz. load. My ounce loads are at 1180 fps.

[Paul Harm]

Pressure changes with different primers varies with different powders or loads. Sometimes a Fed is higher in a certain load, and other times it isn't the highest in another load. There are many loads that will get you what you want with different primers. Looking at the sheet that comes with CBer 3/4oz wads with the same wad, velocity, powder is Titewad :
Ched = 7200psi
Fed = 7900psi
Rem = 6700psi
Win = 6700psi
with Clays powder
Ched = 7200psi
Fed = 7100psi
Rem = 6200psi
Win = 7500psi
Not a whole lot of difference and which one is high and low changes. We also know from Sherman Bell that even Damascus barrel guns aren't going to blow up even with 10,000psi factory loads. So why do I and most of us load low pressure loads? To protect the wood stocks ? Well someone answer this - is it pressure in the shell that the chamber contains or the recoil of heavy loads that crack a stock ? I don't know.
Recoil. True recoil is defined by normal physics : mass of bullet [ and wad ] +mass of powder X velocity = mass of gun X velocity of gun.
Perceived or felt recoil is entirely different. Because the shooter is part of the gun mass because he's holding it invokes many variables. Your posture, how hard the gun is held and your weight. Also how fast a powder burns could make a difference in felt recoil. One time I bought some Remington 1oz target loads at Bass Pro Shop. Thirty boxes of them at $2/box - big sale. One box of them kicking the crap out of me and all were sold for $3/box. They were 1oz, but 1350fps. Factory shells could also kick more because of wads or the powder used. I tried Clay Dot one time and sold the rest of a 8# jug. With the same 1oz load and velocity it felt like it kicked a lot more that what I was use to shooting. If you think less pressure equals less kick, it probably will. Shooting is as much of a mind game as it is physical.

[Gary Laudermilch]

Pressure has no effect on free recoil. Powder burning rate may change the perceived recoil. So many people seem to equate chamber pressure with recoil and often cite the need to protect the old wood. I doubt chamber pressure has any effect whatsoever on the stress the wood endures during firing. An increase in free recoil is likely to put additional stress on the wood. If you want to reduce free recoil the easiest remedy is to reduce the shot charge and/or velocity.

[Daryl Corona]

Bingo Gary.

[William Davis]

As a practical matter only primers I have available are Winchester. Local gun shop stocks them at prices about the same as on line dealers with no haz shipping cost. Remington in 1000 lots over 80 dollars delivered. Winchester half that

On powders I am convinced some powders have more recoil than others. Found some 7/8 oz Federal on sale at Dick’s. Much more felt recoil than my 7/8 oz Red Dot reloads. If the big manufacturers can save a few pennies per box using less volume very fast powder they are going to do it. More expensive 7/8 oz 12 G shells from the Europeans recoil about like my reloads same shot weight. Different components however recoil velocity and pattern I modeled my 7/8 oz after B&P Competition One

William

[Tom Flanigan]

I guess I agree with all of the above. I would still like to see a categorical statement by someone with a relevant degree with respect to pressure and recoil. I'll try to find something. No offense to anyone, but my training is to go to the source for technical information, regardless of the type. All else is hearsay, word of mouth and experiences that may be misleading. I am an IT engineer by training, although my current capacity is director of an IT organization within Verizon. I plan to retire at the end of June.

The Lyman Manual did the primer variance testing to make the point that primers do matter and there should be no deviation from the components listed for each load in the book. Great advice. They took the exact same load and used the different primers to show the difference between them with respect to pressures. My thoughts with respect to the different primer pressures came from this study.

Different powder burn rates probably have an impact on felt recoil. This could be why my loads are so much more comfortable to shoot than the factory loads. My main powders were IMR 4756 and powders with similar characteristics depending on the shot charge I was using. My IMR 4756 is running out so I'll have to get a new manual that has the latest powders in addition to the old that are still available. But I'll still choose the lowest pressure loads.

This has been an interesting conversation.

[Gary Laudermilch]

Everybody's opinion has some merit in a discussion. If you are looking for a definitive answer to the pressure/recoil debate you might try Tom Roster a ballistics engineer with more shotshell experience than anyone I know. I don't know his contact info but it should be available with a google.

As an aside, I am a bit perplexed with your statement regarding the need to get a new manual. As an IT person surely you know that all of the powder manufacturers have web sites with current load data.

[Daryl Corona]

You have to keep in mind that the commercial loadings of the ammo companies load their ammo to higher pressures so as to operate the many jamomatics out there that are probably cleaned once a year. Couple that with the insane desire of the average American shooter for those 1250-1400fps. loads which they think they need to shorten their leads and reach out to 60yds. to break a target and kill a bird.

One of my best friends and long time shooting buddies was an Executive VP, an engineer by trade, at a local defense contractor and did every test imaginable on our handloads and many commercial loads. One of his projects was developing a flechette round for the military. Pressure and velocity were very important.

Anyway, pressure DOES NOT affect recoil velocity does. A simple way to prove it to yourself is to go to any reloading manual and choose two loads with similar ejecta weight and load one with a velocity under 1200fps and near max pressure, say 10,000psi. Then find a similar load going say 1250+fps with similar pressure. Then, and this is important, have a friend load your gun with the test rounds, different loads in each barrel then hand it to you with the action closed. You will of course have marked the rounds to identify them then all you have to do fire the gun twice and compare the recoil. Pressure stresses the metal and recoil hammers the face of the stock and you.

[Tom Flanigan]

Everybody's opinion has some merit in a discussion. If you are looking for a definitive answer to the pressure/recoil debate you might try Tom Roster a ballistics engineer with more shotshell experience than anyone I know. I don't know his contact info but it should be available with a google.

As an aside, I am a bit perplexed with your statement regarding the need to get a new manual. As an IT person surely you know that all of the powder manufacturers have web sites with current load data.

I know that of course. But I like manuals such as Lyman's because information is in there across all manufactures and its easy to compare and find the loads you want. Plus they contain other information which is good to know.

[Tom Flanigan]

Anyway, pressure DOES NOT affect recoil velocity does. A simple way to prove it to yourself is to go to any reloading manual and choose two loads with similar ejecta weight and load one with a velocity under 1200fps and near max pressure, say 10,000psi. Then find a similar load going say 1250+fps with similar pressure. Then, and this is important, have a friend load your gun with the test rounds, different loads in each barrel then hand it to you with the action closed. You will of course have marked the rounds to identify them then all you have to do fire the gun twice and compare the recoil. Pressure stresses the metal and recoil hammers the face of the stock and you.[/QUOTE]

That would be an interesting test to perform and might prove the point, but probably not conclusively. Pure scientific data would prove one way or the other, but I would be willing to accept the results of your experiment. At this point, I tend to lean toward your explanation. It sounds solid.

[Gary Laudermilch]

Since this thread has drifted away from the original question, to which I have added, I'll add a bit more.

An old friend of mine, William C. Davis Jr., now deceased, was a world renowned ballistics expert. He was a neighbor of mine and good grouse hunting buddy. He worked for Colt for over 30 years and in that capacity was instrumental in implementing the changes to the original M16 design to make it more reliable. This was only one of his major accomplishments while at Colt. He was a technical writer for the NRA with numerous articles in the American Rifleman. After retirement from Colt he had a full blown ballistics lab about 2 miles from my house. There was so much electronic gadgetry and pressure barrels in that place that NASA would be envious. He did contract work for the various ammo/arms manufacturers and travelled the world over as a contract forensic ballistician. After I retired he once offered me a part time job. When I inquired about his offer he said he had 100,000 rounds of 357 mag. ammo that needed to be fired. I said "I like to shoot but no thanks"!

Bill was free with information and always willing to answer questions from a neophyte. He knew I was interested in shotgun terminal ballistics and often had me over to his shop to discuss results of my pattern testing. I learned a bunch from that guy but should have paid more attention as I did not learn enough. I wish he were here to participate in this discussion.

Bill and I hunted grouse together on many occasions. He was a confirmed sxs shooter with no preference for any of the US made guns. I never saw him use anything but guns from the big USA firms though. His favorite grouse gun was an LC and boy was it rough. And interestingly enough, I never saw him use a double that was not Damascus. I think he knew something long before others did.

Anyway I wish he were here to add to this discussion. You would have enjoyed it. I miss him and this discussion brought up old memories.

[Tom Flanigan]

It would have been great to have someone with expertise like Bill’s on this thread. As we get older, we lose more of our friends. It never abates and I hate it. I miss all of my friends who have passed. I also miss the many bird dogs and retrievers I have had over the years. I remember them all and think of them often. I especially miss my two all-time best grouse dogs, Rusty and Stoney. They were both grand gun dogs and real characters.

Heaven for me would be a Tinkhamtown type experience with both Rusty and Stoney leading the way. Rusty was my first bird dog and Stoney came much later. Hardly a day goes by that I don’t think of them and the others. I was blessed for sure.

[Paul Harm]

I quoted from a 2004 Accurate Reloaders Guide about pressure does not effect recoil. Here it is:" Recoil: This is certainly the most discussed aspect of the shotgun shooting sport, and this is understandable so, because it determines the " comfort " of shooting hundreds of rounds in quick succession. Because it's such a subjective issues/subject, the conclusions and recommendations are most of the time unfortunately shrouded in confusion, and corrupted by improper comparisons.
Normal physics still do apply, and in this case Newton's Third Law: For every action there is a equal and opposite reaction. Formula: Mass of bullet+ mass of powder X velocity = mass-gun X velocity-gun. "
I don't see pressure anywhere in the formula. They go to write about the shooter, because he's holding the gun, becomes part of the equation. This is where felt recoil comes into play.
So, I'm not just giving my opinion, but quoting what a powder company has written in a reloading manual. Hope this clears a thing or two up.

[Gary Laudermilch]

This one of the best and easiest to use recoil calculators I have found. Additionally, it does a fair job of explaining free recoil calculations.

http://www.omahamarian.org/trap/shotshellenergy.html

You can easily play around with different parameters to see the effect they have on free recoil. You will quickly see that shot charge, velocity, and gun weight are the parameters that have the most effect with shot charge being the most significant. You will also see that chamber pressure has no bearing on any of the calculations.

[William Davis]

Physics aside I vote for Shot charge and Gun weight making the significant difference with recoil. Reason is range of variables are much larger than powder charge. With a 12 G You can shoot a 6 lb or 9 lb gun. Load can vary from 3/4 to 1 1/4 oz. Powder charge minor differences.

William