Re-sizing question

[jsthntn247]

I have started annealing after every firing upon advise from several high master shooters. I measure and bump shoulders only .001 with a Redding body die for ease of chambering during match situations. My load is not hot, 45.4gr Varget with 155gr bullets in LC and Lapua cases. However, my brass is growing .010 in length after each firing. My question is Is the brass growth due to annealing too much (used 750 templiaq for dwell time in flame ) or the fact that the body die is sizing/working the brass too much each time ( the body die sizes .0035 under fired demensions)?

 

[nastynatesfish]

Are you saying the shoulder moves .035 each firing? If so I'd check your chamber. I don't think you need to anneal that often either bi did my 243 wssm 1 time every 5-6 reloads on the brass.

 

[BoydAllen]

The amount that your cases are reduced in diameter when they are sized is definitely a contributing factor. One more thing that you should look at is that if you set a die with un-annealed brass, you you will get more bump at the same setting with softer brass. I see this with my PPC cases when comparing new to work hardened, where the difference, with the same die setting can be .0025 in bump.

 

[jsthntn247]

I measured 4 points along the body with my calipers then ran the brass in the body die. The 4 points were measured again and were .0035 to .004 smaller. The shoulder is only moving .001 forward but I'm having to trim .009 to .010 off each case.

 

[BoydAllen]

IMO you should closely monitor the thickness of your brass in front of the head, looking for signs of incipient separation. That is where the material is coming from that is being trimmed. Also, depending on your chamber neck diameter and the clearance of the necks of your ammunition, you need to look for doughnuts and neck thickening in general, although with the 155s even if you have doughnuts it will probably not be a problem. On the other hand, if you switch to longer bullets, it might be.

 

[SmokinJoe]

I think annealing along, with excessive sizing, is probably making your case growth worse than it could be. If you try annealing less & get your die opened up a little to more closely match your chamber it might make a major improvement. You didn't say whether this was a bolt gun or autoloader, that would make some difference, too. I would try annealing after 3 firings & see how consistent the shoulder bump & neck tension seem. If it stays consistent through 3 firings, try 5. Keep experimenting until you optimize your process. Be sure of your shoulder bump setback. As was said, bumping multiple fired brass & freshly annealed brass are worlds apart; always check, check, check.

 

[jsthntn247]

How many firings can I expect from the brass with .009 stretch each firing? I'm not going to anneal this time and see how much stretch I get.