[Gunnut45/454]

Gentlmen
I have a question for you. I just got a chorograph and started testing my loads that I want to use for Mulely hunting this year. Problem- 454 SRH loaded with 255 gr LFN, 27.5 grains H110, OAL 1.640. shot the following string.

1. 1572
2. 1532
3. 1412
4. 1423
5. 1343
6. 1272

Why did the velocity drop on every shot? This is the only load that did this. This was not cuased by loading practice as I wiegh every load. OAL was consistant. Cast bullets were uniform. All from wheel wieght. Suggestion ?

I shot three short strings of 45 LC 230 LTC, 454 250 XTP, 454 250 LRN, but they had very consistant numbers -good loads.

45 LC
1. 1104
2. 1119
3. 1102

454 250 XTP
1. 1487
2. 1488

454 250 LRN
1. 1273
2. 1289
3. 1377

 

[JRR]

Hello Gunnut45,
My best guess is that the extreme recoil is causing the bullets to work out of their crimp. As the number of shots increases, the looser and longer the remaining cartridges get, reducing the pressure and therefore the velocity.
Just speculation,
Jeff

 

[Chief RID]

I posted earlier but it didn't take. My guess is fouling with the lead load. If you are not getting lead fouling then I think the recoil idea is a good one but it will be a good one to check by chambering one round at a time. Single shot style.

 

[MikeG]

I vote crimp-jumping. Load a cylinderful, shoot all but one, stop, take it out the last one and look.

By the way.... that looks to be a pretty light load with that bullet weight in the .454, or did you mean 355gr bullet?

 

[Gunnut45/454]

Mike G

No that's correct -255 FN Cast! I'm working up on this load since I just got the chrony and it a FB bullet I don;t want to shoot a heavy load right off and get stripping. I have shot some earlier loads at beginning charge wts and they all stripped- so I backed down and started lower as I was working with the mix. I think now I have a bullet that will let me get to where i want to be with out stripping. I'm trying to push this to about 1600 or so. No leading since I'm casting out of wheel wieghts-dropping in water-hard bullets Crimp might be it-though I put a heavy one on them, next sesion I try the single cart at a time see what I get. Thanks.

 

[MikeG]

What size is the expander? It should be 0.004" - 0.006" less than bullet diameter for good bullet pull.

 

[Gunnut45/454]

MikeG
I haven't miked the expander-I'll see what it is. But I took the advice from above and loaded and shot one at a time and the loads where alott more consistant mid 1400's. So I'm thinking bullet creep was the problem. Thanks!