doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Barrel regulation problem

I hate to pop your bubble but there are some things even a buzzard won't touch.

Many years ago I had a very long conversation with Jack Rowe a well known gunsmith in this country. Many of you know him. He ssid not to use a rest or a steady mount when patterering a shotguns. His reasoning at that time was this from what I recall

You snap shoot a shotgun, you do not aim it like a rifle. When you are aiming using a bench rest the sight is different that quickly thowing it up and shooting.

Many folks do not mount the gun in the same position each time when they throw it up. I have seen this myself in my shop. If you do not mount the gun cosistently in the same plase when you shoot, how can you determine where the gun shoots.
Maybe Jack is correct. What do you guys think

John Boyd
Quality Arms

John: I think Jack might be correct only because that is the way the Eyster's who have been competition choking shotguns for years do just that. Normally, they have the shooter shoot their gun free hand. And when checking point of impact, they have the shooter shoot a 5-shot group and where the pattern is most dense is that spot of POI. All this is done free-hand. When assessing the pattern itself and rechoking of the gun, single shots are taken with the shell one intends to use in the gun. For example, I had a Browning Superposed 20 bore choked for grouse hunting with Remington Express #7 1/2 shot. As a result of Ken Eyster's (he is now deceased) work, this Browning throws superior patterns with Remington Express at 25 yds for bottom barrel and 30 yds for the top barrel. This is the method they use for all their competition choking of shotguns and they never use a bench rest. Also, they have you shoot your gun on water in assessing poi. I have found Shooting at an object on water useful in assessing where a gun shoots for me. As in all things, there are many ways to skin a cat, but I think the way the Eyster's do it is pretty scientific and effective.

I'm not doubting this Ted, but would like to understand why a barrel would throw a slug away from the center of a shot pattern of the same load weight/velocity fired from the same barrel when held with equally deliberate "aim". The unstated assumption here is that your brother's gun prints that left barrel pattern where it should. Have patterns been fired from this gun with the same steadily aligned hold as with slugs, to remove fit as a significant variable?

I don't discount anecdotes as valid indicators, but they don't explain. I'd like to understand what the Bruchet's did and why.

Jay (After quite a few years I have to ask Ted ... hasn't the Chas. bit gotten kinda stale?)

I was on the phone with Eyster's today and they suggested shooting POI without a rest. They draw a vertical line from the center dot on the pattern sheet down to the bottom. The shooter points the barrels at the bottom of the line and brings the bead up along the line to center, stops when the bead reaches the center dot and pulls the trigger.

An instructor told me of a different free-hand method that he thought corrected the tendency to tilt your head over the comb when "aiming" for POI. If right-handed, face the pattern sheet in a rifleman's stance, and then mount and point the gun at a target high and slightly to the left of the pattern sheet (~70 degrees above horizontal, and 10 o'clock to the pattern sheet). Bring the gun down to the center dot and pull the trigger.

I have heard several stories from gunsmiths about getting different POI patterns on a gun than the pattern sheets sent to them by clients. It sure seems simple in theory . . . .

Surely in this day and age, someone must have invented a gizmo that could use lasers or something to measure barrel concentricity and alignment? Rocketman, are you looking for a new project?

Not Ted, but a slug normally is of lighter weight & with a higher velocity than the standard shot charge for the gauge. Thus bbl times are different & undoubtedly bbl vibrations are also different. If the load "Always" went to exactly where the bbl was pointing at the instant the trigger was pulled all doubles would cross-fire & would never hit point of aim.

Thanks Miller, didn't mean to limit the question to Ted. Understood about shot charge weight and velocity, and I noted these being equal in my question. Since this match is missing for a gun meant to shoot heavier/slower loads you'd have to determine whether their calculated recoil differs and allow some variance for this. Considering the effort the question becomes academic I guess.

I didn't consider barrel vibration, not thinking factors affecting minutes of angle levels of accuracy were in play for shotgun distances.

Jay

You don't use a bench rest when working up loads or zerooing in a double rifle for the same reasons - the gun is designed to be shot from the hands and thereby accommodate muzzle flip. It's a lot easier to see this with a DR where there are only 2 holes in the target after firing both barrels.

The Bruchets sat down at a bench and fired slugs at a range of 55 yards or so. They used a process where the chokes the customer specified were cut while the gun was being regulated. When it was over, they had a gun that put slugs into the black area of the paper (the black area being about a 4" round spot in the center) and whatever chokes Mr. Customer selected, for use with birdshot. Then, the gun went in for proof.

It looked like a pain in the ass. I sold exactly 1 R11 slug gun in my decade plus of importing Darne guns, it was well documented by Mr. Bodio in the article he wrote on the gun for The Double Gun Journal.

Sorry, Jay. I know who "Gunflint Charlie" was to you and thought you might appreciate someone remembering.
Thats all.

Best,
Ted

I think POI of shotguns should be established by shooting off-hand as they are shot at game/targets. Numerous shots per barrel should be shot to get a statistical average.