Is this a cratered primer?

earthquake · May 14, 2023

CCI 450 in Alpha OCD Dasher brass, first firing.

My go-to load of 32.0-gr Varget. It's an older barrel I cut from 26" down to 18".

4 of 20 rounds for zero and quick test had hard bolt lift. The rest were butter. Not sure why. All the brass is virgin: I ran it all through my die and over a neck mandrel like always. ES was 12, SD was 4.2 fps. They average 2,890-fps from the 18" tube and this same load was going 2,960 when it was 26" long.

Wonder if I should back off 0.4-gr or what?

All 20 primers pretty much look like this though. But they haven't been flattened.

hafejd30 · May 14, 2023

Definitely cratering

Looks a bit flattened

Maybe ejector mark on other side?

pfl338 · May 14, 2023

Your primer cup is flowing back around the firing pin into the firing pin opening. My large firing pin bolt assembly on my AXMC does the same thing. Not really harmful unless you start pushing the limits on pressure, then you will end up with a pierced primer, and it only takes a few of those to start flame cutting the firing pin and that makes the problem even worse. And I know this from experience lol.
One way to solve it is to have your bolt bushed to close down the gap between the pin and the hole.

lash · May 14, 2023

Also, that primer does look a bit flattened to me.

Shouldered barrel or barrel nut? Headspace exactly the same or shorter? Longer?

hafejd30 · May 14, 2023

Send to LRI and have it bushed. Did that on my buddies 6.5 CM savage and it fixed it. Quick turn around as well

That gun would crater primers at mild loads

This advice doesn’t mean bush it and load at high pressures. Still may want to back off a bit if having issues

Near miss · May 14, 2023

Different manufacturers make different primer holes. In that brass it is almost possible to get the primer to really fill the void.

RTH1800 · May 14, 2023

If you need ask..

earthquake · May 14, 2023

lash said:
Also, that primer does look a bit flattened to me.

Shouldered barrel or barrel nut? Headspace exactly the same or shorter? Longer?

Shouldered Proof prefit in a Bighorn TL3. Come to think of it, I had SAC cerakote the barreled action and I haven't taken the barrel off since getting it back from them. I just assumed they'd know how to torque it back on properly. I should probably check it though.

Raufoss · May 14, 2023

It’s a Bighorn, they all do that. Not an issue

hafejd30 · May 14, 2023

The primer cups on certain brands can play a factor in the severity of this issue as well. CCI tend to hold up decent

Some weaker cups could blow the crater out, into the action and pit the pin or the bolt head though

Mike Casselton · May 14, 2023

Raufoss said:
It’s a Bighorn, they all do that. Not an issue

No, they all Don't do that.

earthquake · May 14, 2023

Apparently Alpha OCD brass is a smaller volume than old standard Alpha brass... according to a buddy. Guess I need to back off from 32.0-gr.

Doom · May 14, 2023

If you have hard bolt lift it doesn't matter if the primer is cratered or not. Hard bolt lift is pushing 70 KSI.

nn8734 · May 14, 2023

earthquake said:
Apparently Alpha OCD brass is a smaller volume than old standard Alpha brass... according to a buddy. Guess I need to back off from 32.0-gr.

When you chopped the barrel you lowered the pressure threshold on your charge weight curve, all other things equal. Whatever charge weight you were using (32g) was within acceptable pressures at 26” but is now excessive at 18”. Back off 1.5g or so then work back up in .2 or .3g increments.

Raufoss · May 14, 2023

Mike Casselton said:
No, they all Don't do that.

I have 4 and they all do

Mike Casselton · May 14, 2023

Raufoss said:
I have 4 and they all do

Then you need to contact Ray or you have an issue with your ammunition.

I'd be willing to bet you reload for them and get higher than expected (book) velocity with your loads.

Supersubes · May 14, 2023

What bullet, 105? Seems oddly fast @26”, with too little drop off after the chop. You shoulda lost 150-200 fps, but instead you lost 70. Huge red flag. Pressure peaks in a barrel pretty early in the burn, like 12” down the barrel. Ive chopped many barrels, and never seen one spike pressure after the chop. Something else is going on.

Krob95 · May 14, 2023

I’ve run 31gr Varget and 105’s, alpha ocd dasher brass. Every primer in two different barrels is cratered slightly. ATX and Terminus Zeus. I pay no mind to it. I ran up to 32.4gr in my ATX and the primers didn’t look any worse than 31gr. Just wanted the slower node.

Holliday · May 14, 2023

earthquake said:
Apparently Alpha OCD brass is a smaller volume than old standard Alpha brass... according to a buddy. Guess I need to back off from 32.0-gr.

That certainly is news to me.

I have one lot of standard and one lot of OCD I am using in rotation. Now I need to check some things……

nn8734 said:
When you chopped the barrel you lowered the pressure threshold on your charge weight curve, all other things equal. Whatever charge weight you were using (32g) was within acceptable pressures at 26” but is now excessive at 18”. Back off 1.5g or so then work back up in .2 or .3g increments.

Again news to me. Shorter barrels develop pressure sooner??

nn8734 · May 14, 2023

Max said:
Again news to me. Shorter barrels develop pressure sooner??

Glad you’re getting the news, better late than never…

Supersubes · May 14, 2023

Max said:
That certainly is news to me. I have one lot of standard and one lot of OCD I am using in rotation. Now I need to check some things……

Again news to me. Shorter barrels develop pressure sooner??

If that was the case, all load data would be developed by the manufacturers in short barrels, or there’d be disclaimers about using a “long barreled” load in a short barrel. No such disclaimers exist.

Holliday · May 14, 2023

nn8734 said:
Glad you’re getting the news, better late than never…

Or it could just be bullshit

Boatninja · May 14, 2023

More pressure in shorter barrel doesn't sound right to me, seems like it should be just opposite.
I definitely would like to know.

Chris1972 · May 14, 2023

I know I’m new here but more pressure in a shorter barrel is not a thing. Period. Read any book on reloading and see where the pressure peak is at. It’s certainly now down the barrel and if it was shorter would mean less pressure.

Supersubes · May 14, 2023

DOES MY SHORTER BARRELED RIFLE REQUIRE DIFFERENT RELOAD DATA?

We often get this question. In asking, the customer is unsure if the different barrel length will necessitate a loading data change in the powder chosen. Let’s preface the answer with a quick guide on testing data. All our data is tested for Pressure and Velocity with instrumented equipment as...

hodgdon.com

Supersubes · May 14, 2023

Max said:
Or it could just be bullshit

For sure!

Chris1972 · May 14, 2023

Unless your shootings a megamagnum peak pressure is at or before 3” of bullet travel. The longer barrel will make it faster though. Expanding gasses will continue to accelerate the bullet until internal and external pressure equalizes.

Haney · May 15, 2023

nn8734 said:
When you chopped the barrel you lowered the pressure threshold on your charge weight curve, all other things equal. Whatever charge weight you were using (32g) was within acceptable pressures at 26” but is now excessive at 18”. Back off 1.5g or so then work back up in .2 or .3g increments.

"When you chopped the barrel you lowered the pressure threshold on your charge weight curve, all other things equal. "

Can you provide proof this is a true statement ?

supercorndogs · May 15, 2023

nn8734 said:
When you chopped the barrel you lowered the pressure threshold on your charge weight curve, all other things equal. Whatever charge weight you were using (32g) was within acceptable pressures at 26” but is now excessive at 18”. Back off 1.5g or so then work back up in .2 or .3g increments.

hafejd30 · May 15, 2023

earthquake said:
Apparently Alpha OCD brass is a smaller volume than old standard Alpha brass... according to a buddy. Guess I need to back off from 32.0-gr.

Assuming from this statement you swapped brass after the chop? If so this could very well be the issue. Especially if you load tested either on virgin vs fired brass as the ability to expand can be effected depending how you size vs factory brass.

Thicker brass obviously has less capacity thus will result in higher pressure from same powder charge

If you have old brass try some tests with that to see where pressure signs are. Or even just test with water to determine case capacity of each

Doom · May 15, 2023

If everything was the same and barrel length was the only thing that changed you should have dropped about 240 fps. But you have changed cases and barrel length and dropped only 70 fps so pressure has to have increased significantly. According to GRT you would need to be running in the neighborhood of 70,000 psi to get that velocity if you are running a 105. It would be extremely unusual for cutting a barrel to increase pressure. I also would be surprised if your cases' volume is the only thing contributing to this. You are talking more that 10% decrease to get this response. Assuming you are not in the lands then something is going on with your powder measurement. I am assuming that there is no carbon ring and you checked the case OAL.

Baron23 · May 15, 2023

nn8734 said:
When you chopped the barrel you lowered the pressure threshold on your charge weight curve, all other things equal.

Was about to object to this statement but I see it was adequately pounded into the dirt already! haha

BJames · May 15, 2023

earthquake said:
CCI 450 in Alpha OCD Dasher brass, first firing.

My go-to load of 32.0-gr Varget. It's an older barrel I cut from 26" down to 18".

4 of 20 rounds for zero and quick test had hard bolt lift. The rest were butter. Not sure why. All the brass is virgin: I ran it all through my die and over a neck mandrel like always. ES was 12, SD was 4.2 fps. They average 2,890-fps from the 18" tube and this same load was going 2,960 when it was 26" long.

Wonder if I should back off 0.4-gr or what?

All 20 primers pretty much look like this though. But they haven't been flattened.
View attachment 8141182

I have a Remington 700 SA that does this with literally everything. Hot, starting, middle of the road, and even factory loads. Doesn’t matter brand of primer or brass. I emailed the very well known shop who built it, and was told that it’s just sloppy firing pin hole tolerences. I could send it in for a bushing job and it would go away. But wouldn’t affect anything as long as my loads were reasonable. The first barrel (6.5 cm) went 4200ish rounds.

Imo, your primers look great, though that’s not a great indicator of pressure. Might have an ejector mark on the brass, though hard to tell from the pic. Bighorn stuff is great, but I suspect there might have been a QC issue along the way, at least on my Origin. Mine doesn’t do that, but has its own issues, still love it though.

Precision Underground · May 15, 2023

Looks to me like it’s typical flow from a firing pin gap. If you were shooting LRP brass and swapped to SRP brass, this would likely be new to you. Primers alone are not a good indicator for pressure.

The hard bolt lift could be an indication but if only the first 4 had heavy lift, I’d guess you had just cleaned the rifle and there was moisture/oil or something still in there at first. If it was 4 random rounds out of the 20, that’s prob an indication that you’re too hot. I don’t shoot dasher so I’m not sure if the speed is excessive but the comparison from 26” to 18” seems to suggest you’re hot.

earthquake · May 15, 2023

hafejd30 said:
Assuming from this statement you swapped brass after the chop? If so this could very well be the issue. Especially if you load tested either on virgin vs fired brass as the ability to expand can be effected depending how you size vs factory brass.

Thicker brass obviously has less capacity thus will result in higher pressure from same powder charge

If you have old brass try some tests with that to see where pressure signs are. Or even just test with water to determine case capacity of each

Yeah, it's all brand new unfired Alpha OCD.
105 Berger hybrid.
The only change was a shorter barrel and new brass.
Used to shoot normal Alpha brass and it's all garbage now. Have had lots of issues with it in the past.

earthquake · May 15, 2023

Doom said:
.... Assuming you are not in the lands then something is going on with your powder measurement. I am assuming that there is no carbon ring and you checked the case OAL.

Jumping about 0.020" which I've always done. I went with an old OAL from my notebook.
Pouring powder with an Autotrickler setup like always.

Holliday · May 15, 2023

earthquake said:
Apparently Alpha OCD brass is a smaller volume than old standard Alpha brass... according to a buddy. Guess I need to back off from 32.0-gr.

Because this was news to me, I checked in with my contact at Alpha.

“ Max,

Are you running large or small primer? We increased the capacity of the LRP last run to match the SRP. There would have been a card in the box of brass if you had the new LRP design.

Best,

Tom
Alpha Munitions “

I am running older lots so this is not a factor for me. Thanks for bringing this up because it will factor in when I purchase more Alpha brass soon.

earthquake · May 15, 2023

Back out here with lighter loads.
Cleaned the barrel last night.
Loaded:
x10 @ 30.5-gr
x10 @ 30.8-gr
x10 @ 31.4-gr
x10 @ 31.6-gr

First 5 from the lowest load (30.5-gr) had hard bolt lift, velocity averaged 2800-fps. Thought maybe it was pressure from bore cleaner but I patched it until dry. Second five from that load cycled fine.

First 5 from load two (30.8-gr) cycled like butter, shot well and averaged 2825-fps. Next 5 from that load had hard bolt lift and ejector marks again. SD was 5.1 after 10 shots, max spread was 15-fps. I'm stumped. I'm probably not going to shoot the rest.

I've been fighting brass issues with this gun for over a year now.

earthquake · May 15, 2023

Front to back, right to left is the order I shot these. The ones with primer visible had hard bolt lift, the ones with case neck up were fine. Although there is no difference in the appearance of the bases between the two. Even ones that had no issues with bolt lift show primer flow and ejector marks.

earthquake · May 15, 2023

Well I couldn't resist....I shot 'em all. Funny thing though....the hottest load, 31.6-gr had none that gave me any trouble with bolt lift.

Necks up = ran fine.
Primers up = hard bolt lift
Shot low to high, right to left.

lash · May 15, 2023

I’m just curious if you compare the headspace measurement on these fired case to those from your old brass, before barrel was cut, will there be a difference?

Supersubes · May 15, 2023

Is this virgin brass from the same lot as the brass you wore out previously? If the new brass is thicker than the old, this may he your issue. What’s your loaded round neck diameter versus the chamber neck diameter? Necks typically spring back after firing about .001 or slightly less, so the fired neck is a pretty good indicator of chamber neck diameter.

earthquake · May 15, 2023

Supersubes said:
Is this virgin brass from the same lot as the brass you wore out previously? If the new brass is thicker than the old, this may he your issue. What’s your loaded round neck diameter versus the chamber neck diameter? Necks typically spring back after firing about .001 or slightly less, so the fired neck is a pretty good indicator of chamber neck diameter.

This is all brand new OCD. The old shit was standard Alpha that had several/many firings on it. I trashed it all.

Precision Underground · May 15, 2023

earthquake said:
Well I couldn't resist....I shot 'em all. Funny thing though....the hottest load, 31.6-gr had none that gave me any trouble with bolt lift.

Necks up = ran fine.
Primers up = hard bolt lift
Shot low to high, right to left.
View attachment 8141880

I don’t think the powder charge is what’s giving you a heavy bolt. Are you sure there’s no moisture anywhere near the rifle? No rain/fog/condensation/etc anywhere? It only takes a tiny bit of moisture in the chamber or on the case to spike pressure. I’ve had the follower on mags get CLP on them and give me random pressure when it transfers to the case. Are you cleaning every trip?

I wouldn’t read much into the primer flow. Our Desert Tech leaves the exact same flow with SRPs. It’s just empty space between the pin and the hole.

That being said, if you’ve been fighting with different brass for a year it may just be an issue with the chamber or bolt. Especially if you’ve been fighting the same issue with other brass.

Doom · May 16, 2023

earthquake said:
This is all brand new OCD. The old shit was standard Alpha that had several/many firings on it. I trashed it all.

A couple of questions. Did you run this last batch over the chronograph? If you did what were the result?

As for the primers cratering I don't think its a big deal my Rem 700 craters any load about this the same and its never been an issue.

I don't know what's going on here. The velocity says you are very high on pressure for that barrel length. You are definitely see pressure signs with bolt lift. You have ejector marks. All this says pressure but I'm wondering if it's something with the cases. Before I shoot any more I would clean them before loading.

You mentioned having the rifle cerakoted and maybe having the barrel removed may be central to the issue. Can you check the fired brass Datum dimension and compare it to the "old barrel" dimension?

RTH1800 · May 16, 2023

nn8734 said:
Glad you’re getting the news, better late than never…

Can you please explain the process where the bullet determines what is in front of it? Inquiring minds want to know.

Mudflap621 · May 16, 2023

You are being redirected...

This is worth a read. Seems like there are more than a few people having pressure issues with the OCD brass and certain chamber dimensions.

earthquake · May 16, 2023

Here are the measurements on the brass with primers removed.
Virgin = 1.210"
Fired = 1.215"
Velocity of the 31.4-gr set was about 2,850-fps. ES/SD was 15/4.4 fps.
5 shots:

earthquake · May 16, 2023

Mudflap621 said:
You are being redirected...

This is worth a read. Seems like there are more than a few people having pressure issues with the OCD brass and certain chamber dimensions.

A very interesting read, thanks for that. I'm curious now about the mentions of bolt thrust due to cases not grabbing the chamber walls. I am seeing a lot of brass coloring on my bolt's face that I've not seen in the past.

Mudflap621 · May 16, 2023

earthquake said:
A very interesting read, thanks for that. I'm curious now about the mentions of bolt thrust due to cases not grabbing the chamber walls. I am seeing a lot of brass coloring on my bolt's face that I've not seen in the past.

I’d suggest maybe backing off on the charge and jamming the lands on a few and see if it’ll change heavy lift.

Also if you have micrometer be interesting to see web diameter new vs fired.

Watch Out for Scammers!

Is this a cratered primer?

Area Man

Supporter

Luv2#Steel....

Swamp Rat

Supporter

Major Hide Member

Supporter

Area Man

Sergeant

Supporter

Team Beer and Donuts.

Area Man

Balding Eagle

NN8734

Sergeant

Team Beer and Donuts.

Heathen

Black Multicam Master Race

Old Salt

NN8734

Heathen

Old Salt

Gunny Sergeant

Private

Heathen

Heathen

Private

tokay444, soundless screams . The irony .

Ham Fisted Gorilla

Supporter

Balding Eagle

Check 6

Supporter

Rifle Gear

Area Man

Area Man

Old Salt

Area Man

Area Man

Area Man

Swamp Rat

Heathen

Area Man

Rifle Gear

Balding Eagle

Supporter

Supporter

Area Man

Area Man

Supporter

Similar threads