bat sv problem

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badazl

Guest
I have a Bat sv action for a f-class that started out a 6x47 lapua. I had frequent misfires on new brass especially with CCI 450 so switched to wolf smp, and didn't have as many. but still would have them.
I re-barreled to a 6.5x284 and for 1500 rounds never once had one. Now I went back to 6x47, again the misfires start again. I've had headspace checked and it's fine. What can I do?
 
Have you called BAT? You may not know it but as popular as they are, there is a thriving cottage industry that modifies BAT firing assemblies, for top end benchrest competitors, by adding weight and cutting additional clearances. It sounds like yours has marginal energy, and the easiest fix would probably be a stronger spring. I would start by calling BAT, and if you want something more trick perhaps Dwight Scott or Wayne Campbell.
 
badazl....You stated that you have miss-fires when using new brass...it is very common for new brass to be significantly smaller/shorter than a chamber cut and fitted with a headspace gage...if you are using twice fire brass and are not bumping the sholder back too far...your problem will most likely go away...If you only use new brass when shooting your rifle, then you will need to set you load for at least a .015" jam into the lands to keep the brass from moving forward in the chamber as the firing pin strikes the primer..


Eddie in Texas
 
eww1350 said:
badazl....You stated that you have miss-fires when using new brass...it is very common for new brass to be significantly smaller/shorter than a chamber cut and fitted with a headspace gage...if you are using twice fire brass and are not bumping the sholder back too far...your problem will most likely go away...If you only use new brass when shooting your rifle, then you will need to set you load for at least a .015" jam into the lands to keep the brass from moving forward in the chamber as the firing pin strikes the primer..


Eddie in Texas
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Eddie I agree with what your saying, but there are 4 other guys who shoot with me, and their rifles are cut with same reamer and used same no go gauge. and none of theirs misfire. It also will not misfire if you jam them really hard in rifling, but more then 15 thousands, because that's what I got them now.
 
badazl said:
Eddie I agree with what your saying, but there are 4 other guys who shoot with me, and their rifles are cut with same reamer and used same no go gauge. and none of theirs misfire. It also will not misfire if you jam them really hard in rifling, but more then 15 thousands, because that's what I got them now.
Click to expand...

The three most common causes of misfires are 1) not enough firing pin fall-does not pick up enough speed to have required energy, 2) insufficient firing pin protrusion from the bolt face-does not penetrate the cup enough to activate the charge, and 3) insufficient firing spring strength-see one above.

These should be 1) at least 0.240" fall on most actions, 2) 0.045-0.055" protrusion on most actions, and 3) at least 20# compression force on most actions. Notice I said most actions. Since the BAT SV has a shorter bolt and lighter firing pin than most actions so the three items above are even more critical on the SV than most actions.

All this plus the CCI450 is one of the tougher cups used on rifle primers.
 
If there was never a misfire with the 6.5x284 and the problem only happens with the 6x47 and it can be cured by jaming
bullets hard in the lands, it would seem clear that the culprit is the operator on the handle of the loading press.
 
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