Grins and Giggles with Two Barrels and Big Balls
07-19-2018, 05:35 PM
#14
Typical Buck
Join Date: Apr 2017
Posts: 984
Find the load that is the most accurate for both barrels then you find your regulation point. DBML's are hard to do this because of all the variables in loading. Getting the exact same pressure on the push down, powder within a grain, nipples allowing the same amount of fire through, even slight variations in the patch lube can cause different speeds. You will have to be getting as red neck close as you can basically. And no, faster or slower will not effect regulation. They are still traveling at the same geometric line and will come to meet at the same point. Faster or slower won't affect that. Only thing speed will effect is elevation of where each barrel will hit not windage. It's getting both barrels to hit at the same point consistently that is difficult with ML's because of previously stated reasons.
07-19-2018, 05:58 PM
#15
Boone & Crockett
Thread Starter
Join Date: Apr 2007
Location: River Ridge, LA (Suburb of New Orleans)
Posts: 10,917
The reason I believe increasing velocity will cause convergence farther from the muzzle is that increased velocity means increased recoil. With two barrels side by side and the sight in the middle, wouldn't increased recoil cause the right barrel to recoil a bit to the right and the left barrel recoil a bit to the left?
07-19-2018, 06:12 PM
#16
Spike
Join Date: Feb 2016
Posts: 56
I know your ML is a shotgun and not a rifle - so who knows how or even if it was regulated to converge at one spot. To boot - you don't have any rifling.
I've owned 1/2 dozen original British BP double rifles over the years - now only 2, both cased and 1 is RB double (actually a belted ball). Whether BL or ML you can find the regulation (which is part of the fun) by bullet weight (conicals) and powder charge - yes POI will move. Slowing down will actually cause the projectile to stay in the bore longer; i.e. right bbl will go right & left to left. Faster will be the opposite.
I wrote and article for the NMLRA MuzzleBlast a few years ago, that was published Nov. 2107 titled "Three Deuces" - all 45 fast twist double rifles. Alexander Henry, John Rigby and a Whitworth.
I'll be curious to your testing as ML double rifles are nothing new - been around for 200 years +/-.
I've owned 1/2 dozen original British BP double rifles over the years - now only 2, both cased and 1 is RB double (actually a belted ball). Whether BL or ML you can find the regulation (which is part of the fun) by bullet weight (conicals) and powder charge - yes POI will move. Slowing down will actually cause the projectile to stay in the bore longer; i.e. right bbl will go right & left to left. Faster will be the opposite.
I wrote and article for the NMLRA MuzzleBlast a few years ago, that was published Nov. 2107 titled "Three Deuces" - all 45 fast twist double rifles. Alexander Henry, John Rigby and a Whitworth.
I'll be curious to your testing as ML double rifles are nothing new - been around for 200 years +/-.
07-19-2018, 06:16 PM
#17
Boone & Crockett
Thread Starter
Join Date: Apr 2007
Location: River Ridge, LA (Suburb of New Orleans)
Posts: 10,917
Well, it's going to be an easy test. Shoot both barrels with 65 grains of powder at 25 yards, then both with 85 grains. Then I will know the "hole" truth. 
07-20-2018, 06:35 AM
#18
Spike
Join Date: Feb 2016
Posts: 56
The 8” group at 25 isn’t ideal, but you should be able to reduce and maybe eliminate the crossing.
Have fun, that’s what’s most important.
