Blown primers on 6.5 CM-Problem Solved on page 6!

[Stonyman88]

My final notes are a little neater than my worksheet notes, this is how I track my measurement.

LOVE the new work sheet, I use old prescriptions bottles to keep my fired brass with the pill & info in , and also on a sheet like yours, Great looking sheet

 

[lyle2231]

I'm doing some load development on a 6.5 CM Christensen Arms Mesa, with a 22" barrel. This rifle has approximately 300 rounds, and has been easy to develop loads for. I have developed loads for Nosler 140 AccuBond at 2734 fps with 41.2 grains of H4350, with 3-round groups at sub .400 moa, and SD of 6. I also have a load with Nosler 140 grain BT, 41.0 of H4350, .360 moa, an IMR 4350 load below .400 moa. All of these loads had zero pressure signs, and MV in the low to mid 2700 fps.

Today I try some load development with Hornady 143 ELD-X, H4350, Nosler brass, Federal 210 primers. I begin at 41.1 grains of powder, with intent of going to 41.8 in 0.10 increments, shooting for accuracy. Hodgdon site has 41.8 of H4350 as their max load.

At my first load at 41.1, I blow the primer. Thinking that was an fluke, I fire two more, both with blown primers. This is below my 140 grain AccuBond and BT loads that have zero pressure signs, and 0.7 grains below the Hodgdon site max loads. I pulled the rest of the loads and reloaded, starting at 40.3 grains of H4350. I can't believe that 41.1 grains of H4350 is over pressure. Any thoughts?

How many times have the brass been fired?
With hotter loads the primer pocket will loosen up.

 

[tim_w]

How many times have the brass been fired?
With hotter loads the primer pocket will loosen up.

He had them jammed into the lands.

 

[lyle2231]

He had them jammed into the lands.

My experience…Pressure can be reduced slightly by shorter OAL. IF it were me I'd go twenty thousands back into the case. See if it pops the primer if it doesn't work then drop a half grain of powder, load up with the shorter round and try it. HTH

 

[JAYgs8163]

My experience…Pressure can be reduced slightly by shorter OAL. IF it were me I'd go twenty thousands back into the case. See if it pops the primer if it doesn't work then drop a half grain of powder, load up with the shorter round and try it. HTH

Read page 6. He's figured it out!

 

[lyle2231]

Read page 6. He's figured it out!

Thanks

 

[skipglo]

I'm doing some load development on a 6.5 CM Christensen Arms Mesa, with a 22" barrel. This rifle has approximately 300 rounds, and has been easy to develop loads for. I have developed loads for Nosler 140 AccuBond at 2734 fps with 41.2 grains of H4350, with 3-round groups at sub .400 moa, and SD of 6. I also have a load with Nosler 140 grain BT, 41.0 of H4350, .360 moa, an IMR 4350 load below .400 moa. All of these loads had zero pressure signs, and MV in the low to mid 2700 fps.

Today I try some load development with Hornady 143 ELD-X, H4350, Nosler brass, Federal 210 primers. I begin at 41.1 grains of powder, with intent of going to 41.8 in 0.10 increments, shooting for accuracy. Hodgdon site has 41.8 of H4350 as their max load.

At my first load at 41.1, I blow the primer. Thinking that was an fluke, I fire two more, both with blown primers. This is below my 140 grain AccuBond and BT loads that have zero pressure signs, and 0.7 grains below the Hodgdon site max loads. I pulled the rest of the loads and reloaded, starting at 40.3 grains of H4350. I can't believe that 41.1 grains of H4350 is over pressure. Any thoughts?

It's the brass! Had the exact thing happen this week. Exact! First time for me to use Nosler brass. My go to load is 143 eldx 41.5 gr. H4350...been shooting that till my Hornady brass started getting tired this past week. Loaded Nosler same way....only loaded 5 to test...blew two primers. Internal volume is tighter only answer!

 

[lyle2231]

It's the brass! Had the exact thing happen this week. Exact! First time for me to use Nosler brass. My go to load is 143 eldx 41.5 gr. H4350...been shooting that till my Hornady brass started getting tired this past week. Loaded Nosler same way....only loaded 5 to test...blew three primers. Internal volume is tighter only answer!

Brings to mind when AR's became popular. Federal range brass compared to WCC brass. WCC brass load applied to the Fed brass = blown primers.

 

[bomberodevil]

It's the brass! Had the exact thing happen this week. Exact! First time for me to use Nosler brass. My go to load is 143 eldx 41.5 gr. H4350...been shooting that till my Hornady brass started getting tired this past week. Loaded Nosler same way....only loaded 5 to test...blew two primers. Internal volume is tighter only answer!

The Nosler brass may have contributed to the increased pressure, but in my case, a math error had me seating the bullets .030" longer than I thought, likely right on the lands. I can't blame Nosler brass.

 

[skipglo]

The Nosler brass may have contributed to the increased pressure, but in my case, a math error had me seating the bullets .030" longer than I thought, likely right on the lands. I can't blame Nosler brass.

It's not blame...just something I was unaware of. Great you figured it out! Happy shooting!! But if you were into the lands I would have expected a tight bolt as the first clue...strange! But you got it now.

 

[M1A1ABRAMS]

typically just ahead of the casing in the freebore you can get carbon buildup... the dreaded carbon ring. I just had to give my 7rum the what-for the other day because it wasn't just building a carbon ring, but a ring AND filling the first couple inches of rifling with heavy carbon. Took a good bit of soaking and a few hundred passes with an oversized bronze brush to cut the deposit out.

You don't use CLR ? Primal Rights library offers this

The Evolution of Barrel Cleaning :: Primal Rights, Inc

There are so many different methods, tools, and opinions on rifle barrel cleaning that it would be virtually impossible to even mention them all. Barrel cleaning is quite possibly one of the most argued topics in the precision rifle world. The only thing more impressive than the number of...

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[Lefty7mmstw]

You don't use CLR ? Primal Rights library offers this

The Evolution of Barrel Cleaning :: Primal Rights, Inc

There are so many different methods, tools, and opinions on rifle barrel cleaning that it would be virtually impossible to even mention them all. Barrel cleaning is quite possibly one of the most argued topics in the precision rifle world. The only thing more impressive than the number of...

www.primalrights.com

Nope... I use #9 and a brush for most cleanings... I'll burn the copper with Barnes solvent or similar once in a while when I see more than trace amounts in the bore. I'm a firm believer that solvent alone will NOT attack burned in deposits hard enough to remove them. I've had to JB paste quite a few of the overbore barrels too if I can't get the fouling out with three or four series of brush/ patch cleaning.