OP
OP
WrongHanded
Member
- Joined
- Jul 6, 2017
- Messages
- 4,771
Report:
I went back to the Lyman 50th starting load of the lever gun data. Which was:
43.5gr of H322 under the 405gr coated LRN-FP from SNS Casting. They have the velocity in a 24" barrel as 1,469fps. My barrel is about 18".
I double checked the barrel before shooting to ensure it was clean. It was. 20 rounds later, and I had leading again, in the last 4-5 inches.
I've decided to put these bullets aside for now. I did notice SNS are now casting at .459", but mine are .458". I bought 150 Berry's plated 350gr bullets, which are supposed to be good to 1,700fps. I will try these. 350gr makes more sense to me anyhow, as the ammo I have selected for field use (purely defensive), is either jacketed or semi-jacketed, and at 350gr.
I think I'll just get rid of the remaining coated lead I have (which is actually closer to 200, and not the 400+ I thought). No big deal to avoid scrubbing lead out of the barrel again.
There is a small possibility that some discontinuity in the barrel where the dovetail is cut for the front sight, and where the magazine tube lug is brazed/soldered, is causing the issue. I think I'm seeing a little rippling on the barrel interior there. But both of those are closer to the muzzle than the leading begins, so it seems unlikely.
My inexperienced guess would be a combination of the bullets being a little small in diameter, and the velocity exceeding that relatively small purchase on the lands, is causing the bullet to break free of the rifling at a certain velocity. This would make sense, as with the lower powder charge, the leading appeared to start closer to the muzzle than what I found at the 50.0gr charge. I suppose that getting higher pressure could cause the bullet base to obturate and eliminate the leading entirely. Or it might just cause more of it along a greater distance of the barrel. I'd rather not take the chance.
I went back to the Lyman 50th starting load of the lever gun data. Which was:
43.5gr of H322 under the 405gr coated LRN-FP from SNS Casting. They have the velocity in a 24" barrel as 1,469fps. My barrel is about 18".
I double checked the barrel before shooting to ensure it was clean. It was. 20 rounds later, and I had leading again, in the last 4-5 inches.
I've decided to put these bullets aside for now. I did notice SNS are now casting at .459", but mine are .458". I bought 150 Berry's plated 350gr bullets, which are supposed to be good to 1,700fps. I will try these. 350gr makes more sense to me anyhow, as the ammo I have selected for field use (purely defensive), is either jacketed or semi-jacketed, and at 350gr.
I think I'll just get rid of the remaining coated lead I have (which is actually closer to 200, and not the 400+ I thought). No big deal to avoid scrubbing lead out of the barrel again.
There is a small possibility that some discontinuity in the barrel where the dovetail is cut for the front sight, and where the magazine tube lug is brazed/soldered, is causing the issue. I think I'm seeing a little rippling on the barrel interior there. But both of those are closer to the muzzle than the leading begins, so it seems unlikely.
My inexperienced guess would be a combination of the bullets being a little small in diameter, and the velocity exceeding that relatively small purchase on the lands, is causing the bullet to break free of the rifling at a certain velocity. This would make sense, as with the lower powder charge, the leading appeared to start closer to the muzzle than what I found at the 50.0gr charge. I suppose that getting higher pressure could cause the bullet base to obturate and eliminate the leading entirely. Or it might just cause more of it along a greater distance of the barrel. I'd rather not take the chance.
