Misfires during fireforming

adamsgt

adamsgt

Jerry Adams
Made up 15 new cases to fireform today. Using the bullseye w/wax method. The first round failed to fire. Tried a couple of times more and no go. The second one fired as did the rest up to number 9, 10 and 11 which misfired. Numbers 12 through 15 fired OK. I had visually checked all 15 for powder before sealing. I removed the wax from #1 and confirmed it was full of powder. There was a visible hit on the primers that should have been sufficient. So the possible causes are bad primers. Which I hope is not the case because I took these out of my range reloading box. Another thought is that this is the first time that I have taken the firing pin out of this Bat bolt. Don'r know if I could have done something wrong putting the firing pin back in. All the rounds felt the same when chambering. Headspace was OK on the misfires. Had a crush fit. What else should I be looking at? :confused:
 
FBecigneul said:
If you neck turned these and used oil as a lubricant, the oil can contaminate the primer and render it useless. Did you clean and dry the cases before you loaded them up?
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I hadn't neck turned yet. I wanted to blow the shoulder forward and neck trim then. I did expand the neck and then used a .261 bushing when I sized the cases to adjust the headspace for fireforming. I used a q-tip and imperial die wax inside the neck for expanding. I used a bore mop inside the neck before priming, but I did NOT wash and dry the cases. I thought the bore mop would be sufficient. Evidently not, so I may have gotten some of the lube down around the primer hole on the inside of those cases. That seems to be the most plausible explanation. Thanks Francis. That's why I only did 15 in case I had some screw ups.


Jerry Adams
 
Are you sure you had a crush fit?

Let me rephrase this..... are you sure you had ENOUGH crush fit??? You need a pretty good lip for it to hold. Re-check the ones that didn't fire and see if they still feel tight..... iron a layer of masking tape onto the casehead and see if it'll still close easily....

al
 
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How do you " adjust" headspace with new brass?? If these are new 220 Russian cases for a 6PPC, I have noticed a lot of headspace using a case HS gage because the shoulder needs a lot of blowing out to fully fireform. This may cause the case to move forward so far on contact from the firing pin that it does not detonate.
 
zimmden said:
How do you " adjust" headspace with new brass?? If these are new 220 Russian cases for a 6PPC, I have noticed a lot of headspace using a case HS gage because the shoulder needs a lot of blowing out to fully fireform. This may cause the case to move forward so far on contact from the firing pin that it does not detonate.
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When I put the new brass in the gun and move the bolt forward it stops where the bolt handle is about 1/4 to 1/8 inch short of the slot in the action. So I gradually adjusted the sizing die until the bolt handle was above the slot and could start downward. When I went to actually fireform I had to use a fair amount of downward force to get the bolt to close. It's actually more of a "crush" fit than I am comfortable with. It's hard to quantify just how hard the crush was in words but I feel it was more than sufficient.

Al, on the misfires, I still had resistance to overcome to close the bolt. The bolt handle didn't just drop in. On the first time around I had to "palm" the bolt handle pretty good to get it closed.
 
Jerry, You said you did not neck turn the brass first. With a .261 neck you should have necks about .0082. New Lapua brass has necks about .0125 to .013. Perhaps the crush you feel is the thick necks being forced into the tight neck chamber. Did you check case headspace before and after firing? Is this Lapua brass for a 6PPC ? Bob Z
 
Here's some column B thinking. The BAT SV actions have been reported to be marginal on firing pin strike. A couple respected smiths (who do have a financial incentive in fixing BATs) have reported that even some of the 7.5-inch models can be a bit weak on ignition.

OK, suppose (1) this is correct, and (2) under normal conditions, you're right on the edge. That would explain why you're getting a few misfires fireforming, and more important, that your regular ammunition could be made to perform better if the firing pin system were reworked.
 
Bob z, Because I wasn't seating bullets for the first fireform I didn't need to turn the necks yet. That was to be my next step.

Charles, I'm beginning to suspect my priming tools. I usually prime with a hand held APS strip tool. However for these I used a bench mounted APS tool that I acquired on ebay. I reprimed the four that failed with the hand held tool and they all went pop with just the primer. Prepped the four and took them to my workshop and three of the four fired. Went back to my house and reprimed the stubborn one using my sinclair hand tool and the primer popped. Loaded that one up but have to wait until after my physical therapy in about 30 minutes. I think I also need to clean out the bolt and firing pin. Could be a combination of things. Maybe I dislodged some dirt when I removed the firing pin the first time.
 
Well, the last stubborn round went of with a satisfying bang. I'm now fairly convinced that the problem lies with primer seating. I need to check the two APS seaters and adjust as necessary. I removed the firing pin again from the bolt. It's fairly greasy and I think I'll spray it out with some aerosol cleaner. However, what type of lube is best, how much and where does it go?
 
Another thing to consider is primer sensitivity if everything else is a bit dodgy. I have a rifle that required WSR primers for regular ignition when fireforming. They always went bang when others wouldn't. Alternatively the cases can be necked up to .25 cal or 6.5 mm then sized back down to 6 mm leaving a little false shoulder when that's done. Not much but it helps.
 
Larry Elliott said:
Another thing to consider is primer sensitivity if everything else is a bit dodgy. I have a rifle that required WSR primers for regular ignition when fireforming. They always went bang when others wouldn't. Alternatively the cases can be necked up to .25 cal or 6.5 mm then sized back down to 6 mm leaving a little false shoulder when that's done. Not much but it helps.
Click to expand...

What brand of primer are you using? It can make all the difference.

Scott
 
Use that Sinclair priming tool and stuff 'em in until they bottom out. If you continue to have problems send your bolt to a BR gunsmith and tell him to fix it.
 
I think that (what Wilbur said) about sums it up. Federal primers have worked for me when others did not, so about all that's left is the possibility that the primers are not seated deep enough to be sensitized or a light firing pin strike. Wouldn't hurt to measure the firing pin extrusion.
 
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