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annealing brass and meplats

26 Apr 2013
@ 06:05 pm (GMT)

stephan bieganek

I have read and watched videos of you annealing bullets. What do you think of annealing brass? Also what is your thoughts on meplats how important is it with regards to accuracy and efficiency. I read a article on it and they indicated that there can be a 2 - 8% increase in BC. http://www.appliedballisticsllc.com/B_7mm_180Hyb.html. Thank you for all the previous replies.

Replies

26 Apr 2013
@ 07:11 pm (GMT)

Quote this

Nathan Foster

Re: annealing brass and meplats

Hi Stephan, I have answered the annealing brass question in the general discussion thread, will cut and paste below:

Pan of water, halfway up the case.
Blow torch (and pan) as per bullet annealing video in KB
I set the vise so I can walk around it, I do one case at a time.
Apply heat to the shoulder and neck, once the case neck goes dull cherry red, I rotate the blow torch around the case so that the cherry color goes around the case neck.
It is easiest to do this in a low light, prevents going overboard and making the case so soft that the shoulder collapses during bullet seating!

Wait 5 seconds
Remove case from water with a welding glove or very gently with light poly grips on case body. lay on a towel. Case needs to cool slowly to anneal.

Either allow to dry naturally or oven dry at a very low temp. If you have annealed unprimed cases, be very careful of water trapped in the case, it can really get locked in the case. It is preferable to anneal fired cases while the dead primers are still in the case.

I then resize and decap the cases. Because the above method is not performed in a controlled environment, there is the potential for variations in neck tension which may effect ES or subtly effect accuracy. Therefore, if doing load development, treat the freshly annealed cases as 'preliminary development'. The cases will then be uniform in neck tension after firing and re FL/Neck sizing.

There are various methods and home inventions on youtube. Some folk use a lee cutter shell holder and a cordless drill, others have different ideas. Whatever you do, make sure the case head has a heat sink (why I use water) as this area needs to remain somewhat hard. If incipient case head seperation (circular case split) occurs at the case head (or just forwards of the belt on magnums), it is a sign of over working brass in your press versus a long head space rifle. Back the sizing die off in the press to remedy this.

As for meplat trimming, when I trim a projectile, the BC is going only going to go one way- down. That is because I trim to increase frontal area for terminal performance. I will sacrifice BC for increased terminal performance. I don't do it for accuracy as I have never had trouble with the meplat as an accuracy variable. There are far greater evils to contend with.