Dasher primer piercing HELP

[Monday shooter40]

I have found the firing pin protrusion to be excessive on several Impact Actions. One was close to 0.080" as I recall. I trim them to just under 0.050" if they are too long. If you haven't checked that, its worth a try.

.059 the best I can measure. I do not have a micrometer depth gauge. Used the back of my calipers.

 

[Monday shooter40]

Thanks everyone for your thoughts and ideas. I’m still working on this. Will update later today.

 

[LRPV]

Thanks everyone for your thoughts and ideas. I’m still working on this. Will update later today.

I was not talking about freebore length I was talking about the diameter. Sometimes reamers are spec’d with a smaller diameter than needed for proper clearance if you get a batch of fat bullets.

 

[FeMan]

.059 the best I can measure. I do not have a micrometer depth gauge. Used the back of my calipers.

That is too long then IMO and could well be the problem or part of it.

 

[Alex Wheeler]

I completely understand that case capacity is not the same between Lapua and Alpha. But I should be able to run a 105 hybrid at 2850 with Varget without piercing primers in a 26” barrel in either case brand. I ran load work ups in my old barrels that went WAY beyond these speeds, just trying to find the ceiling. And I did. But for whatever the reason is, if these barrels won’t run a 105 at 2850, then i guess it is what it is and I will pull these barrels and my lesson will be learned. I’ll keep my notes and be sure to avoid this combination of barrel/reamer.

I just ordered another barrel from another gunsmith who uses a different brand of reamer. My gunsmith seems to be just as confused at me. I’ve been chasing this for weeks with no other conclusions besides I’ve changed barrel manufacturers and reamer designs. I’ve also changed brass manufacturers.

I’ve loaded a work up test in one of my older Lapua lots that I will shoot later today. I will report back.

Piercing primers is not a pressute sign but since all you changed was brass and barrel you obviously have much higher pressure now. But you shouldnt be piercing primers even if the pressures high. You have a problem in the ignition that the higher pressure has shown you. Check pin fall and spring. May need to tear it down and check for other issues too.

 

[Monday shooter40]

Update:

Piercing primers is not a pressute sign but since all you changed was brass and barrel you obviously have much higher pressure now. But you shouldnt be piercing primers even if the pressures high. You have a problem in the ignition that the higher pressure has shown you. Check pin fall and spring. May need to tear it down and check for other issues too.

Lapua brass behaves better. But dare I say it’s great. Primer impacts appear erratic, however they are not as raised as bad as they do with alpha. I ran two loads in two different lots of Lapua. 31.2 and 31.5 grains of Varget, that averaged 2832fps / 2853 (5 shot averages) Again this is a 26” brux Dasher running 105’s with Varget and Cci 450’s.

Just for yucks. I ran the two lower charge weights in Alpha brass as well. 31.0 and 31.2 grains of Varget. Speeds were very close to Lapua test 2838 and 2852. The erratic primer cratering is there as usual. Some have none. Some have minimal. 2 had large amounts. I took the best photo I could of one of the bad alpha cases.

Both brands of brass shot well on paper and velocity SD/ES were great.

I know I do not have the correct tools to measure pinfall and my firing pinhole diameter. However, the best I can measure my pinfall is around .266” and my firing pin diameter is .067 and the hole is .0695. I know that using a set of motto to calipers is not the correct way to measure a firing pinhole but it’s all I have at my house at the moment.

My gunsmith does not like my firing PIN numbers and wants me to bring him my rifles later this week so we can measure them properly.

Thank you everyone again for your input.

 

[243winxb]

Weak firing pin springs?

 

[Monday shooter40]

Weak firing pin springs?

I think I found the problem…… My previous firing pin springs I changed out after ~ 5k rounds. They seemed ok. Nothing drastic, but they were definitely shorter than new ones out of the package by about 1/2” (didn’t actually measure)

My latest firing pin springs, one has about 400 rounds and the other has ~ 800 rounds, are are about a full inch shorter than new springs.

I even recently bought a complete spare firing pin assembly so that if I run into trouble at a match, I can just change and go. This spring was compressed as well, and it has zero rounds on it.

I overlooked the firing pin springs because of how relatively new they are. Thanks for voicing opinions guys! It steered me in the right direction.

 

[243winxb]

Check pin fall and spring

Said before me. The photos made me think of springs.

But the length of springs can be very confusing.

Buying Springs from the manufacturer of the action/bolt would seem to be a good idea?

 

[Monday shooter40]

Said before me. The photos made me think of springs.

But the length of springs can be very confusing.

Buying Springs from the manufacturer of the action/bolt would seem to be a good idea?

All these springs came from the action manufacturer directly. It’s clear that they switched springs at some point. It might not be visible in the photo, but you can clearly see that there’s a color/material difference.

 

[Monday shooter40]

Another update: problem not fixed with brand new firing pin springs. Pierced another primer today and ruined another firing pin. I’ve run the same load in matches before through this exact rifle. 31.8 gr Varget , Virgin Alpha , Cci450, 105 hybrid it averages 2890. The load shoots fantastic, if you take away destroying firing pins.

Back to the drawing board.

 

[Straightshooter1]

Another update: problem not fixed with brand new firing pin springs. Pierced another primer today and ruined another firing pin. I’ve run the same load in matches before through this exact rifle. 31.8 gr Varget , Virgin Alpha , Cci450, 105 hybrid it averages 2890. The load shoots fantastic, if you take away destroying firing pins.

Back to the drawing board.

Am curious, as I've not ever had any issue with my firing pin due to some pierced primers, though last April was my first and only experience with pierced primers. In early April I had 3 pierced CCI400 primers in a series of 10 new Alpha brass I was testing. I haven't seen any kind of effects from it on my firing pin for over 300 firings now. And I've inspected it closely with a magnifying glass.

What about your firing pin makes it "ruined"?

 

[LRPV]

Time to screw an old barrel back on to see if it goes away.

 

[Monday shooter40]

Am curious, as I've not ever had any issue with my firing pin due to some pierced primers, though last April was my first and only experience with pierced primers. In early April I had 3 pierced CCI400 primers in a series of 10 new Alpha brass I was testing. I haven't seen any kind of effects from it on my firing pin for over 300 firings now. And I've inspected it closely with a magnifying glass.

What about your firing pin makes it "ruined"?

I can’t get my camera to focus on the end of the pin. But it deforms the tip. It cuts off a corner and pushes it back.

 

[Monday shooter40]

Time to screw an old barrel back on to see if it goes away.

Also on my ‘to-do’ list.

 

[Monday shooter40]

Forward progress! I have solved/mitigated this problem 2 ways.

Solution #1 to rifle#1: bought a new barrel chambered with an Alpha Legacy reamer. This barrel will run the same loads that were previously problematic, with out extreme cratering and piercing primers. My other barrels were chambered with a PTG “Alpha” spec reamer. My guess at the solution here is that my fired brass @ the .200 line is .002/.003 different. The problem barrels having the larger fired brass. Something about the dimensions of the PTG reamer and alpha brass do not like each other in my experience.

Solution #2 rifle #2: I bought a new bolt from Impact (against Tate’s advice) with a .060 firing pin. I can run previously problematic loads in alpha brass without severely primering craters and/or piercing them.

I had a hunch that my problems were related to my new barrels/reamer. I still can’t definitively define the “why”. But changing barrels/reamers solved the problem with my std .068 bolts.

My ‘problem’ barrels still shoot lights out. I just have to run them with the small firing pin bolt.

Thanks to everyone for helping.

 

[Ccrider]

Forward progress! I have solved/mitigated this problem 2 ways.

Solution #1 to rifle#1: bought a new barrel chambered with an Alpha Legacy reamer. This barrel will run the same loads that were previously problematic, with out extreme cratering and piercing primers. My other barrels were chambered with a PTG “Alpha” spec reamer. My guess at the solution here is that my fired brass @ the .200 line is .002/.003 different. The problem barrels having the larger fired brass. Something about the dimensions of the PTG reamer and alpha brass do not like each other in my experience.

Solution #2 rifle #2: I bought a new bolt from Impact (against Tate’s advice) with a .060 firing pin. I can run previously problematic loads in alpha brass without severely primering craters and/or piercing them.

I had a hunch that my problems were related to my new barrels/reamer. I still can’t definitively define the “why”. But changing barrels/reamers solved the problem with my std .068 bolts.

My ‘problem’ barrels still shoot lights out. I just have to run them with the small firing pin bolt.

Thanks to everyone for helping.

I would have sent it all to a smith that knows so that I could be confident that my ignition was right.