question on steel shot

[charlie cleveland]

ive dabbled a bit in loading steel shot and a question has poped up in my mind i can not answer...does any of the steel shot coming down the barrel of a gun get ahead of the wadding or does it stay inside the wad till it leaves the barrel when fired....if it stays inside the wad till it exits the barrel how could it possibly i cause damage to the barrel if the barrel is of a modified or less in choke...just wandering.... charlie

[Dennis]

Charlie, I am a new member who hasn't a lot of experience with steel shot but do have an idea. Whether it is correct or not I can't say. In my opinion since steel does not compress as lead does it will eventually, with continued firing, wear out the chokes of a fine gun. That is unless the gun is made of somewhat harder steel such as my Merkel 20 gauge. As an aside I remember when I was 14 years old and my parents bought my twin brother and I, each of us, a Winchester Model 37 20 gauge shotgun. They were and are fine guns. I decided one day to try my own brand of reloading and loaded up some ball bearings into a shell from which I had removed the lead shot. Upon firing the gun at a target there was increased recoil but not a lot of hits on the target. When my brother and I looked down the barrel there was no mistake we/I had done something bad. The bore was pockmarked for most of the length. It still shot well after that but it was always embarrassing trying to explain the pock marks in the barrel.

[charlie cleveland]

dennis i know most steel shot is harder than some barrels that are made of softer steel but how can the steel harm the barrel if it is in a good plastic wadding...the steel should never touch steel if enclosed in a good wadding...i know that you might harm a full choke gun but a modified or lesser choke should be fine in my way of thinking..ive checked steel wadding after they had been fired i seen no damage to the wad so if no damage to wad how can there be damage to the steel barrel if shot through a open choke gun regardless of steel the barrel is made of... i also have shot steel balls through some old guns it is good we learn from our experiances in life... charlie

[Dennis]

My thinking is only that if the steel shot does not compress within the shot cup it still, by friction, wears against the bore. The plastic cup protects the bore from steel rubbing against steel but not from the friction of the steel not compressing. It simply wears on the bore gradually, diminishing whatever choke is in the barrel if it is a tight choke. That is the best this old guy can explain it. Darn it, now you have me thinking about it more and more. Remember I really don't know anything about this so this is only a thought on my part. Is there a real ballistician in the crowd??? Anyway that is my thought on it.

[Big Friend Ten (BFT)]

Charlie and Dennis,

1. The shot cup SHOULD keep any shot within it due the inertia of the shot and the movement of the wad down the barrel. Shot may however slip between or wear through the petals of the shot cup and score the bore.

2. Any steel shot will score a barrel lengthwise if it comes in contact with the barrel. If you load steel #7 shot in your favorite target wad please expect to scar your barrel. If you do not then consider yourself lucky! Wads hard and thick enough for steel shot are required!

3. First generation steel was loaded with inadequate wads that allowed shot to slip or wear through the wad petals. Roster patented a wad in 1987 that eliminated most of this problem for modern high carbon barrels. Your Parkers have LOW carbon barrels and are at risk if you shoot steel in them! First generation steel loads will likely cause problems in Parkers.

4. First generation steel shot would also rust into a steel slug which split a lot of barrels.

5. Plastic wads will not wear a barrel because the barrel, no matter how soft (low carbon content) the material is, is in fact orders of magnitude harder than the barrel. It would be like rubbing your palm on hardwood. Your skin will wear off before the wood is worn away. This is why plastic wad material must be occasionally removed from older, non chrome barrels. Older barrels are rougher than modern chrome lined barrels.

6. Everything is a spring per Young's Modulus, http://en.wikipedia.org/wiki/Young's_modulus . Even steel shot will compress under enough force. That does not happen in older barrels. The barrels must strain or temporarily expand to allow the shot and wad to pass through. ALL barrels do this even with lead shot. If however a barrel expands to the point of stress, PERMANENT deformation will occurred. Obviously barrels with less choke constriction will pass steel easier. Small steel shot MAY readjust itself to pass through barrel constriction. Smaller steel shot will adjust easier than large shot. -- Note: The constriction is what most refer to as choke. Choke is the performance of the barrel, constriction, shot, wad, velocity, and perhaps other factors and is measured by the percentage of pellets striking a 30" circle at 40 yards. That is of course another subject.

7. Large steel shot traveling through tightly constricted barrels, even new barrels, may likely cause damage. Something’s got to give!

8. Bridging occurs when the velocity of a column of shot is momentarily is retarded and the expanding gas slips by. This will cut the barrel and cause a split.

9. Ring budges also occur when a column of shot momentarily is retarded. This occurs in thin barrels but could occur in a thick barreled Remington 870!

10. Some of us believe that with enough wad petal thickness and hardness that steel shot can safely be shot in old, low carbon barrels. Research will be conducted over the next few years (Yes years unless someone want to hire me full time to do this!) to provide evidence via controlled tests that certain barrel materials, of certain thicknesses, with certain amounts of constriction, using certain wad thickness/material/hardness, fired at certain velocities/pressures, are safe to shoot steel shot of certain size(s). The results will be published.

ONCE AGAIN: Shooting steel shot in older, low carbon barrels is risky! Certainly the less choke the better when shooting steel in older guns. Wad thickness and hardness is believed to be a significant factor in protecting a barrel from damage. Mylar liners around shot within a really good wad would be best. Do not shoot older factory steel shot loads in Parkers!

[Bruce Day]

I concur about not shooting the older factory steel shot loads in Parkers, or any vintage barrel.

Some have anecdotally reported no ill effects with small steel shot in modern shot cup wads in open choke guns. Testing is in order.

Mark, I thought bridging was when large size shot formed to create a joined mass at the constriction, such as a transverse row of large shot becoming longer than the ID of the barrel. Bridging can occur with any shot material, however, the softer the material( like lead), the more it can compress when encountering the constriction. Are we saying the same thing?

Bridging is the problem when shooting buckshot.

[Big Friend Ten (BFT)]

Bruce,

I think we are in agreement. If a shot column acutally bridged into a solid mass it would open up the barrel like a flower, i.e. steel shot casualities of around 1980.

A bridge is a momentary glob of shot in which the individual pellets do not move. The expanding gas has to go somewhere so it takes the path of least resistance and seeps between the wad and barrel at the weekest point. Much like a shaped charge the gas suddenly reaches an extremely high velocity and cuts like a water jet! The cut weakens the barrel and it splits. No telling what happens to the wad and shot.

Mark

[Bruce Day]

So you are saying that it is a plasma cut rather than a mechanical rupture. Interesting. Regardless, bridging can occur when too large a size of shot is used for the bore......i.e. shooting #2 shot in a 20ga. Therefore the 10 ga.

Early steel shot loads caused many problems which are supposed to be resolved in contemporary loads, however, the horror stories live on.

The only Parker barrel rupture I personally saw and examined was in an Acme 20 ga barrel from RST loads that was very thin, like .008, paper thickness. That was after forward hand position and was a mechanical, jagged, rupture tear, not a smooth cut at all.

[Big Friend Ten (BFT)]

Bruce,

A barrel wall thickness of .008 was an accident waiting to happen! The British proof houses like .020" minimum in the forward portion of the barrels. I like .030" or more. Every collector of vintage guns should have access to a high quality barrel thickness gauge and use it! My Hosford Barrel Wall Thickness Gauge provides data as to what loads/shot size my guns should be safe to shoot. My Hosford gauge also saved one of our well know Parker guys from wasting $4000 on a 16 gauge Parker with thin barrel walls. After measuring he informed the seller and sent the gun back. The seller promptly relisted the gun with NO mention of thin barel walls. In fact, later we saw the gun on the seller's table at the UP shoot!

The gas jet does the cutting to weaken the wall. To be considered "plasma" the gas must be ionized by an electric charge. A charge MAY be induced during firing but I have no information to confirm this. Maybe if the gas jet were ionized a very clean cut would be evident on the bore side of a split in a barrel?

The gas jet may be more like a water jet cutter which uses high pressure water mixed with an abrasive substance to cut. Certainly any of the residuals from shooting that we regularly need to remove from our shotgun bores would serve as the abrasive.

This subject makes me appreciate the importance of a wad with a very good gas seal. Ballistics Products Inc. (BPI) sells a gas seal for 10 gauges called the X10X. Some loading data requires its use between the powder and the wad. When I select my loading data for BB size shot, I will opt for one that requires the X10X or similar high quality gas seal.

The wad design is likely the solution to the problems with shooting steel shot in doubles!

Mark

[Bruce Day]

Originally Posted by Mark Ouellette

Bruce,

..........
The wad design is likely the solution to the problems with shooting steel shot in doubles!

Mark

Yes, and if Roster is correct, he solved that problem in 1987. The wad design plus mod or less chokes.

Looking forward to the verification / test findings. But there is always the Flat Earth Society.