Dasher primer piercing HELP

[Monday shooter40]

I think I know the answer to my own question, but I can’t explain the exact problem/ solution.

Been shooting a dasher for years now. I’ve always used Lapua brass in a “Lapua” chamber (whatever that means anymore). It was time to rebarrel my match rifles and I let my gunsmith talk me into using his Alpha reamer. .274 neck and .120 FB. Brux blanks 7.5 twist at 26” long. I also switched over to alpha brass for these new barrels. I use impact actions (yes I shoot PRS) now I can’t stop cratering the sh!t out of primers and I’ve pierced several. Resulting in damaging several firing pins. I was running 105 hybrids over 31.8 grains of Varget and a Cci 450. It was shooting tiny groups and decent SD’s @ around 2875fps. But like I said, it was inconsistently cratering primers severely and even pierced a few. Now I’ve backed it down to 31.2 grains of Varget @ around 2830fps and it still does it. I’ve tried running Peterson brass in the other rifle and it’s worse. I’ve used virgin Alpha and reloaded several thinking it might be a virgin brass issue, and it doesn’t help. Some cases come out with no cratering at all, and some have raised craters that measure.013 to .0145 tall.

I shot out 1.5 creedmoor barrels and 2 other dasher barrels with these actions before this and never experienced anything like this. Previously I could rely on heavy cratering as a pressure indicator. Either hotter loads or water testing. My only explanation is the difference in reamers. My fired Lapua brass from my old barrels at the .200 line is .469 /.4695 My fired alpha brass from my alpha chamber is .471 /4715. I don’t know if or how that’s a problem but my resized alpha cases measure .469 @ .200 line

I’ve only had these problems since I switched barrels that were cut with this new reamer. I hate to ditch 2 barrels, but I have no other explanation. I do not have clickers or hard bolt lift. I have no other indicators of problems other than primers. Where do I go from here? I can’t rely on these rifles to get through a match without damaging a firing pin.

 

[Straightshooter1]

I think I know the answer to my own question, but I can’t explain the exact problem/ solution.

Been shooting a dasher for years now. I’ve always used Lapua brass in a “Lapua” chamber (whatever that means anymore). It was time to rebarrel my match rifles and I let my gunsmith talk me into using his Alpha reamer. .274 neck and .120 FB. Brux blanks 7.5 twist at 26” long. I also switched over to alpha brass for these new barrels. I use impact actions (yes I shoot PRS) now I can’t stop cratering the sh!t out of primers and I’ve pierced several. Resulting in damaging several firing pins. I was running 105 hybrids over 31.8 grains of Varget and a Cci 450. It was shooting tiny groups and decent SD’s @ around 2875fps. But like I said, it was inconsistently cratering primers severely and even pierced a few. Now I’ve backed it down to 31.2 grains of Varget @ around 2830fps and it still does it. I’ve tried running Peterson brass in the other rifle and it’s worse. I’ve used virgin Alpha and reloaded several thinking it might be a virgin brass issue, and it doesn’t help. Some cases come out with no cratering at all, and some have raised craters that measure.013 to .0145 tall.

I shot out 1.5 creedmoor barrels and 2 other dasher barrels with these actions before this and never experienced anything like this. Previously I could rely on heavy cratering as a pressure indicator. Either hotter loads or water testing. My only explanation is the difference in reamers. My fired Lapua brass from my old barrels at the .200 line is .469 /.4695 My fired alpha brass from my alpha chamber is .471 /4715. I don’t know if or how that’s a problem but my resized alpha cases measure .469 @ .200 line

I’ve only had these problems since I switched barrels that were cut with this new reamer. I hate to ditch 2 barrels, but I have no other explanation. I do not have clickers or hard bolt lift. I have no other indicators of problems other than primers. Where do I go from here? I can’t rely on these rifles to get through a match without damaging a firing pin.

Did you measure case volumes to see what the difference might be between the different brass?

 

[Cfshooter]

I have no clue, that combo of components have been run in probably thousands of rifles with no issues. I would say something to do with barrel or action, but here to see what others smarter than me have to say about it.

 

[rdremsek]

Ditch the alpha brass

 

[R.Morehouse]

I am running a 272 135fb reamer with both Lapua and Alpha. The new Alpha is loaded with 32.5 Varget and CCI 450 shooting a 103 at 2985 to 3000 with zero issues out of a Bartlein 8T.....I only listed this for some Alpha comparison numbers for you. I don't know why the proprietary Alpha reamer would have issues with Alpha brass.......Do you have any way to measure the reamer to see if it is on spec with the Alpha print?

Regards
Rick

 

[Monday shooter40]

I have no clue, that combo of components have been run in probably thousands of rifles with no issues. I would say something to do with barrel or action, but here to see what others smarter than me have to say about it.

I figured this was a no-brainer and I had an opportunity to pick up a large lot of alpha brass. I have run Alpha brass through my Lapua Chambers with no issues at all. But those barrels are done now. The bad part is, I don’t exactly know how to classify a Lapua chamber. Other than most have a 272 neck and a slightly smaller 200 line. Reamer specs are all over the place and I can’t nail down a definitive comparison.

 

[Monday shooter40]

Ditch the alpha brass

I am going to check that later this week, and load some of my older Lapua brass. If it works, I’ll be even more confused because technically my Lapua brass comes out of my sizing die ever so slightly smaller than alpha brass does.

I’m bitter about it because I just prepped a very very large lot of alpha brass that I was supposed to use for the rest of my year.

 

[Walt Krafft]

What is your loaded round neck diameter and what is your fired case neck diameter? Also what is you case length on the cases with bad primers vs good primers?

 

[762willdo]

The alpha reamer cut you a completely different chamber than your used to so in a sense your learning curve is bent differently…….

 

[Keith Glasscock]

What action? It sounds to me like you have a large firing pin diameter and/or an oversize firing in hole in the bolt face.

I run Alpha brass and 105 hybrids a lot hotter than that without any problems still with 450's.

I suspect you've had this problem all along, but the small flashhole in the Lapua brass was preventing it from blanking primers.

 

[Cfshooter]

What action? It sounds to me like you have a large firing pin diameter and/or an oversize firing in hole in the bolt face.

I run Alpha brass and 105 hybrids a lot hotter than that without any problems still with 450's.

I suspect you've had this problem all along, but the small flashhole in the Lapua brass was preventing it from blanking primers.

Thanks for the tip measuring fired cases, it was a “duh” moment for me lol.

 

[Monday shooter40]

I am running a 272 135fb reamer with both Lapua and Alpha. The new Alpha is loaded with 32.5 Varget and CCI 450 shooting a 103 at 2985 to 3000 with zero issues out of a Bartlein 8T.....I only listed this for some Alpha comparison numbers for you. I don't know why the proprietary Alpha reamer would have issues with Alpha brass.......Do you have any way to measure the reamer to see if it is on spec with the Alpha print?

Regards

What action? It sounds to me like you have a large firing pin diameter and/or an oversize firing in hole in the bolt face.

I run Alpha brass and 105 hybrids a lot hotter than that without any problems still with 450's.

I suspect you've had this problem all along, but the small flashhole in the Lapua brass was preventing it from blanking primers.

Impact actions with .068 firing pins.

My previous dasher and creedmoor barrels did not do this and I ran them much harder(albeit I was running Lapua brass) in the 2900’s . If my older barrels cratered primers , it was consistent and most likely well deserved from hotter loads.

 

[10XSHOOTER]

Bore diameters? .236 or .237 That could make a difference.
I run 32.5 varget with a moly 107 26" barrel 2920 fps.
Defiance Rebel action small firing pin.

 

[misser]

I have experienced popping holes in primers . for me the fix was a JP bolt and Remington #7.5 primers

 

[Lance21]

How many rounds fired since you changed the firing pin spring?

 

[danny]

I think I know the answer to my own question, but I can’t explain the exact problem/ solution.

Been shooting a dasher for years now. I’ve always used Lapua brass in a “Lapua” chamber (whatever that means anymore). It was time to rebarrel my match rifles and I let my gunsmith talk me into using his Alpha reamer. .274 neck and .120 FB. Brux blanks 7.5 twist at 26” long. I also switched over to alpha brass for these new barrels. I use impact actions (yes I shoot PRS) now I can’t stop cratering the sh!t out of primers and I’ve pierced several. Resulting in damaging several firing pins. I was running 105 hybrids over 31.8 grains of Varget and a Cci 450. It was shooting tiny groups and decent SD’s @ around 2875fps. But like I said, it was inconsistently cratering primers severely and even pierced a few. Now I’ve backed it down to 31.2 grains of Varget @ around 2830fps and it still does it. I’ve tried running Peterson brass in the other rifle and it’s worse. I’ve used virgin Alpha and reloaded several thinking it might be a virgin brass issue, and it doesn’t help. Some cases come out with no cratering at all, and some have raised craters that measure.013 to .0145 tall.

I shot out 1.5 creedmoor barrels and 2 other dasher barrels with these actions before this and never experienced anything like this. Previously I could rely on heavy cratering as a pressure indicator. Either hotter loads or water testing. My only explanation is the difference in reamers. My fired Lapua brass from my old barrels at the .200 line is .469 /.4695 My fired alpha brass from my alpha chamber is .471 /4715. I don’t know if or how that’s a problem but my resized alpha cases measure .469 @ .200 line

I’ve only had these problems since I switched barrels that were cut with this new reamer. I hate to ditch 2 barrels, but I have no other explanation. I do not have clickers or hard bolt lift. I have no other indicators of problems other than primers. Where do I go from here? I can’t rely on these rifles to get through a match without damaging a firing pin.

Did you work up your loads all over from the start with the new barrel, or did you just run the same load in the new barrel right from the get go?

Danny

 

[Monday shooter40]

How many rounds fired since you changed the firing pin spring?

Both rifles have new firing pins and springs. They have less than 500 rounds on either.

 

[Monday shooter40]

Did you work up your loads all over from the start with the new barrel, or did you just run the same load in the new barrel right from the get go?

Danny

I ran practice and barrel break ins at much slower speeds. Then started working back up to my match speeds which is only ~2840/2850. That’s when it started getting my attention. I pierced my first primer at 2825 fps. If a dasher can’t run a 105 hybrid at that speed, then there’s a problem somewhere.

 

[FeMan]

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.

 

[Sheldon N]

Loads sound appropriate, I run 31.0 Varget 450's and 105 hybrids in Alpha brass and consider it a conservative load.

I assume you're not jamming the bullets into the lands and that your sized case headspace is not excessive, but those are two things I'd check.

The suggestion about double checking firing pin protrusion is a good one. FWIW my Impact action measures 0.060" firing pin protrusion.

One other thing I've heard is that once a firing pin pierces a primer the tip can become scored/jagged and be much more prone to piercing primers in the future. That could be an issue at play here if you're continuing to pierce primers with the same pin.