Target gun barrels and bore size
 

I have two questions. A little background first. I have a 12 ga that was ordered to shoot trap. It has damascus barrels. Built in 1912. It is completely origianl and unmessed with.

First, why would a shooter order a gun with damascus barrels when steel barrels were in vouge?

Second, the bore size is .734. Would this size be a special order? (I don't know why Parker would just randomly over-bore barrels). If so, would it be shown as a special order in the Parker records? Why would someone order this size?

Thx, Ray

Damcus barrels remained popular for years after fluid steel came out. Some makers would only put them on higher grade guns due to the cost to manufacture

As for the bores, i seem to remember older damascus bore sizes where a little larger than modern standards, maybe these tube were from old stock.

Or maybe -ifthe ordered as a trap gun -the shooter spec'ed it that way.

And didn't Burt Becker 'discover' that over-boring produced better long-range patterns?

IMHO, over-boring and back-boring result in better patterns no doubt. In modern times, the size is much greater. Browning back-bores some of it guns to .742. Mossberg over -bores the entire barrel to 10 ga size. I think they size them at .759. That is a lot more then .734-which wouldn't seem to me to makes that much of a difference although Beretta today claims their barrels at .730 are overbored (there std size is .725).

I just wonder if the .734 would have to be special order and if it was thought to make a difference. With regards to damascus, I guess some folks just liked them.

Also, If after patterning the gun in question didn't deliver the pattern's that were spec'd out Parker Bros. would bore the barrels a bit more to put more choke in the gun.

Quite possibly honed a few thousanths to remove pits from the use of corrosive primed shells, which were what was available for the first twenty years of the guns life. Quite often guns were sent back to Parker Bros. to have their bores "cleaned up" during all the years corrosive primers were in use.

Based on my examination, I don't believe the barrels or chokes were bored. No way to say for sure but the choke size matches the letter and it would have had to have very, very light pits to only need to take out .005 to clean up.

Anything is possible but I think it is the way it left the factory

I summed up the average bore diameter of seven Damascus guns (Parker, Lefever, LC Smith) and I came up with .733.

Of the 14 bores, this ranged from .727 (Pre 13 LC) to .739 (Parker) -- which was probably honed.

Ray, serial number??

I have several PB guns with bores in the .732 - .734 range. My DHE live bird gun is .738.

I agree with Frank and Ed. I have yet to measure a 12ga Parker with fluid steel barrels that are .729, they seem to be in the .731 to .734 range. The majority of 12ga pre S/N 60000 are in the .740 to .760 range, these are top action guns.

Dean, I thought Becker back bored the guns he worked on. Did he over-bore them too?

TPS says that the Std size for 12 ga was .729. Maybe Parker didn't worry about being exact? Seems there are a lot of guns in the .734 range. I guess a few 1000's over made no difference to the machinist. It doesn't seem to me that .005 over would really make much difference. That size is hardly "over bored". Although in these modern times Beretta calls it's gun .005 over bored?

From what I understand, Becker lengthened forcing cones (reducing the angle) and over-bored barrels as well.

According to Michael McIntosh's A.H. Fox book "Becker's Super Fox forcing cones are 3/4-inch long and obliquely angled... Early on, Becker and Askins overbored their 12 gauge Super Fox barrels by .020-inch, from the standard .730 to .750... Eventually, in order to accommodate the widest possible range of ammunition, they established .740-inch as the standard Super Fox bore."

Cheers
Marcus

I believe that over boring to .740-.750 would make a difference. The modern guns that are backbored and overbored, ie Browning (backbored to .742) and Mossberg (overbored to .759), definitely pattern better in my opinion.

I can't see how .734 would make much difference so it may not have been done for any specific purpose.

Over bores
 

I have an under lever 2 frame with .765 bores that deliver beautiful patterns. It's great for long range shots when I do my part. Years ago I had a Stan Baker Perazzi single barrel with an .800 bore I shot trap with.
Cheers, Tom

That Perazzi barrel must have been paper-thin!

Perazzi Barrel
 

No, Stan Baker made the barrel himself, as he did many. I don't remember the wall thickness but it was standard thickness. I don't think the wad had a proper seal as the shot made a goofy sound. The pattern never was real good. Cheers, Tom

I kind of line up behind Researcher on this. It has been my observation that Damascus barrels in particular are oftentimes overbored, and not to anything that smacks of a common dimension. Having reamed out some light pitting myself, I am hesitant to think I am the first.