- Joined
- Dec 12, 2004
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Howdy Folks,
Finally got to burn some more Pyrodex P in our Pedersoli .62cal with PRB. The following loads have proved safe in our weapon but can not recommend their use in any other.
As you may remember we achieved 660fps with 40gr (by volume) of powder.
Today we registered 910fps with 70gr. Clearly, the powder (in excess of 40gr) is not all being blown out of the barrel unburned as some people seem to think it should. It may not be at maximum efficiency of grains burned vs velocity achieved but suits our purposes.
We are now in an acceptable power range for our requirements at a hair singing distance. Mr. BrownBear may find it acceptable for his use as well. With this heavy of a firearm, the recoil is not uncomfortable.
In my usual perfect hindsight, must reconsider Mr. DanChamberlain's comment regarding possible blow bye. The PBR only requires using thumb pressure to get the ball below the mouth of the muzzle. Then they are easily seated with a minimum of effort. Fired patches look good with no evidence of burning/leakage. We had cleaned the bore after each three shot string for velocity average.
Today, I did not clean between each string of shots. The PRBs still seated easily but there was a noticeable difference in the pressure required to seat the ball, as shooting progressed.
Now here's the thing: Just for the heck of it, re-shot the 65gr loading (without cleaning the bore) and the velocity was 921fps! 20+ fps above the 70gr charge. It would appear the small amount of fouling present in the bore was enabling an even tighter seal, resulting in a slightly higher velocity with less powder.
So, after working up a shot load next session, think I will revisit this and try using a lubed wad between the PRB and powder, for a better seal.
Best Wishes
Finally got to burn some more Pyrodex P in our Pedersoli .62cal with PRB. The following loads have proved safe in our weapon but can not recommend their use in any other.
As you may remember we achieved 660fps with 40gr (by volume) of powder.
Today we registered 910fps with 70gr. Clearly, the powder (in excess of 40gr) is not all being blown out of the barrel unburned as some people seem to think it should. It may not be at maximum efficiency of grains burned vs velocity achieved but suits our purposes.
We are now in an acceptable power range for our requirements at a hair singing distance. Mr. BrownBear may find it acceptable for his use as well. With this heavy of a firearm, the recoil is not uncomfortable.
In my usual perfect hindsight, must reconsider Mr. DanChamberlain's comment regarding possible blow bye. The PBR only requires using thumb pressure to get the ball below the mouth of the muzzle. Then they are easily seated with a minimum of effort. Fired patches look good with no evidence of burning/leakage. We had cleaned the bore after each three shot string for velocity average.
Today, I did not clean between each string of shots. The PRBs still seated easily but there was a noticeable difference in the pressure required to seat the ball, as shooting progressed.
Now here's the thing: Just for the heck of it, re-shot the 65gr loading (without cleaning the bore) and the velocity was 921fps! 20+ fps above the 70gr charge. It would appear the small amount of fouling present in the bore was enabling an even tighter seal, resulting in a slightly higher velocity with less powder.
So, after working up a shot load next session, think I will revisit this and try using a lubed wad between the PRB and powder, for a better seal.
Best Wishes
