Jump to content
Brian Enos's Forums... Maku mozo!

"Domed" primers


frankge

Recommended Posts

Had to replace my Grandmaster's 9mm Trubor barrel after a squib did it in. Replaced with another Trubor with Brazos Thundercomp 2 . Noticed primers are now showing a slightly "domed" appearance now. These are with 124 Plated Xtreme HPs with 8.4 of HS-6 and Rem 5 1/2 primers (1.165-68). Same performance across the chrono, seem to shoot the same in a match. Next set of loads will be dropping the charge down a bit. Experience with Rem primers, or is it just the newness of the barrel? 

Edited by frankge
Link to comment
Share on other sites

...Trying this in the reloading section

 

Had to replace my Grandmaster's 9mm Trubor barrel after a squib did it in. Replaced with another Trubor with Brazos Thundercomp 2 . Noticed primers are now showing a slightly "domed" appearance now. These are with 124 Plated Xtreme HPs with 8.4 of HS-6 and Rem 5 1/2 primers (1.165-68). Same performance across the chrono, seem to shoot the same in a match. Next set of loads will be dropping the charge down a bit. Experience with Rem primers, or is it just the newness of the barrel? 

Link to comment
Share on other sites

maybe domed is the wrong term, looks like a slight crater and then a little bump up. Doesnt look like any gas is escaping past the primer and eroding the breechface

9mm1.thumb.jpg.c89a73cb152cd6332fc1fd9ad31ec2f8.jpg

Edited by frankge
Link to comment
Share on other sites

The primers are cratering.  A sign of high pressure.

 

That they are doing it in the new barrel and, I'm assuming, not in the old barrel indicates the new barrel may have a tighter chamber or shorter throat.

 

 

Link to comment
Share on other sites

I figured as much, running Remington 5 1/2 primers - didn't think they were known to be soft like Federals as they are recommended for .40 and .357mag. 9 Major is pretty much high pressure all the time in my experience. Not looking forward to decapping a s#!t load of ammo I have made up already. These are actually the worst looking ones, most are just flat like they  normally would be. I could switch to SRP's that I have but I'm of the school that they just hide over-pressure and sometimes let gas out.

 

Link to comment
Share on other sites

Check to see if the firing pin is the correct size for the firing pin hole. This was a big problem years ago then firing pin holes and firing pins were standardized with firing pins that fit snug in the hole. 

Link to comment
Share on other sites

did the plunk test last night, no problems. Regarding the firing pin hole, deep river customs went through the gun when the new barrel was put in, I'll trust that it was done right. I'm not too worries with some over pressure using SPPs as like I said, most look ok. My new batch will get less powder though and re-chrono. I would think as the barrel wears in a bit that will alleviate the issue somewhat. I'll shoot the new batch first then use up the others which I have ~1000 so I really dont want to decap and reload.

 

Link to comment
Share on other sites

Have you chronoed the new barrel? 

I ran 3 open guns over the chrono the other day with 1 batch of ammo all 125gr bullets, Rem SPP

Gun 1,  1340fps 167.5pf, primers look fine 

Gun 2, 1400fps 175pf, primers pretty flat

Gun 3, 1440fps 180pf, primers cratered like yours 

 

Guns 1 and 2 have similar chambers and throats gun 3 has a shorter throat all have similar barrel length.

 

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...