Dirty gun = Pressure issues?

[DagOtto]

Hi All,

Ive recently had an issue with one of my guns which I believe was related to the guns barrel and/or chamber being dirty. I want to run the scenario by you all and get your thoughts. Ive recently changed my cleaning protocol from once every 10-20 shots fired to once every 150-250 shots fired. This was based on listening to Forms posts here on Rokslide, Shoot 2 Hunt podcasts (both espousers of the “never clean” method,) along with Hornady and GunWerks podcasts (both who suggest cleaning periodically due to their observations that not cleaning can lead to pressure issues.)

My situation in brief:

I shot my 6.5 Creedmore with hand loaded 130 grain Lehigh Defense Controlled Chaos bullets two weeks ago at the range and had 4 blown primers out of 12 shots fired.

Shells were loaded by me at the point of very mild pressure signs. 2800 fps. Ive shot over 100 rounds of this same ammo to date with no issues. Then suddenly on this one day I had stiff bolt lift on all shells and blown primers

Came home, cleaned barrel with boretech eliminator, nothing special, just their recommended procedure. Noted that the chamber and throat seemed very dirty, including chunks of blown primer gunk.

Then yesterday went back to the range and fired 10 shots with zero issues.

My best guess is the dirty gun caused pressures to spike. Seems to fall in line with Hornady and Gunwerks podcast “data.”

But Im a newb and Id expect that Form and Ryan would say that it wasnt a dirty gun issue. So im a bit confounded and curious as to what else it could be and what im missing.

Now: the details:

Brass is all first load Lapua and I did not size the brass. Just chamfered, deburred and loaded. Federal large match rifle primers.

Bullets are seated longer than SAMMI but not into the lands as I had to load to fit the magazine. OAL of 2.32” my measurement hd the lands at 2.334

42 grains of H4350, hand thrown and powder measured for every shell and Im confident that all shells were loaded within 2/10s of a grain. I did buy a second pound of H4350 and noticed some variation in velocity with the second batch of powder. Avg of 2798 for first batch of powder and 2759 for second batch. Loaded 200 total shells. Let me be clear here: Im new to reloading so maybe I f’ed something up. But dont know whay that would be.

Action is defiance Rukus, barrel is 22” proof carbon. Shooting suppressed. Do suppressors increase the back pressure and therefore increase the risk of primers blowing out?

And can I reload those pieces of brass that blew primers or are they toast?

Thoughts?

Thanks

 

[mt100gr.]

Were there any pressure signs at all on the shots prior to those 12? I've dealt with random pressure spikes, too, and found it really hard to narrow down....did I just not notice? Was it random? (Your 12/12 hot loads isn't random...) And for what it’s worth, I've been hand loading for a number of years and still feel like a newb a lot of times.

How long ago did you load those rounds?

I know it was new brass, but are you 100% positive there was no debris in the brass? The worst pressure spike i have seen was when a buddy dumped powder on a bunch of tumbling media...whoa!!

 

[huntnful]

I'd say dirty gun = pressure issues.

Shoot, in pressure. Clean, out of pressure. Very simple and straightforward. No more, no less.

That said, you're probably really close to top end charge, which is why the shift was so drastic. Especially in virgin lapua brass if that's happening. If you want to run hot, you'll likely have to keep cleaning the barrel to avoid those pressure spike. Or drop down a grain or so, and the issue will likely go away.

 

[06 SB]

Been reloading for 40 years and have had pressure issues at times. Your load is close to maximum according to Lehigh's data: 42.5gr of H4350 for 2835MV from a 24" barrel. When I am loading for a rifle, I start low and work up until I hit max powder charge or the posted velocity corrected for barrel length. In your case about 2785MV from your 22" barrel. You are there. You can try a few other things to see if it is pressure or something else. You could back off a full grain of powder and seat your bullet to SAMMI length. If the pressure signs never return you know you were at or over max pressure and the little bit of carbon build up sent pressure way up. If pressure is still present, then it is something else. Try a different primer. CCI and Remingtons tend to not build up pressure as fast IME. When you do these tests, PLEASE wear eye protection...

 

[Billy Goat]

H4350 shouldn't be bad, but hot weather can cause the issues you had too.

Load worked up around 40 degrees, once it's 75-80 what was a hot load but not over pressure will start to go over pressure. Same thing can happen with a warm chamber, letting round sit in the chamber a little bit, or ammo sitting out in the sun.


Likely not what you experienced, but can also happen.

If the brass popped the primers, they might not hold primers again, if primers seat in them properly tho, I'd reuse them. Inspect the primer pockets, try seating new primers and see what happens.

 

[Megalodon]

Were the 12 shots with pressure issues the first after cleaning? Cleaning residue in the chamber can spike pressure. Was it wet when you shot them? Same issue can happen with water.

I personally think you were probably into the lands. If you are trying to load them .002" off the lands there's just too much variation in measurement and loading that could've put those rounds kissing them.


Anyone who says a dirty gun can't cause pressure issues () is frankly a moron. Some are more prone to it than others, examples being carbon rings, but when an entire industry acknowledges there are issues that can spike pressure and you're the only one or two that claim otherwise.... there's your sign.

 

[OverInfinite]

There may be a carbon ring in there. Cleaning the chamber may relieve it just enough to not show symptoms when you were only shooting 10-20 times between cleaning.

 

[DagOtto]

Were there any pressure signs at all on the shots prior to those 12? I've dealt with random pressure spikes, too, and found it really hard to narrow down....did I just not notice? Was it random? (Your 12/12 hot loads isn't random...) And for what it’s worth, I've been hand loading for a number of years and still feel like a newb a lot of times.

How long ago did you load those rounds?

I know it was new brass, but are you 100% positive there was no debris in the brass? The worst pressure spike i have seen was when a buddy dumped powder on a bunch of tumbling media...whoa!!

Hi,
I was close to the top of acceptable pressure with this load. Will be dropping down 1/2 grain or so in future I think. Id typically been getting very slight ejector marks, and pretty flat primers, but not sticky bolts.

I loaded the rounds about 3 months ago.

Im not 100 percent that there wasnt anything in the shells but I did not tumble them and had handled each shell to chamfer and prime. Maybe shavings from thr chamfering? However, im gonna guess this is a low-percent chance of being the issue cause thr issue showed up at one shooting, and hasnt shown up at all in previous 100 or so shots.

 

[DagOtto]

I'd say dirty gun = pressure issues.

Shoot, in pressure. Clean, out of pressure. Very simple and straightforward. No more, no less.

That said, you're probably really close to top end charge, which is why the shift was so drastic. Especially in virgin lapua brass if that's happening. If you want to run hot, you'll likely have to keep cleaning the barrel to avoid those pressure spike. Or drop down a grain or so, and the issue will likely go away.

Thanks, My current theory agrees with you. I am at the high end of pressure. I really wanted to get higher muzzle velocity given cooper bullets need higher impact velocities to perform. So pushed it Too far I guess!

Learning!

 

[DagOtto]

Been reloading for 40 years and have had pressure issues at times. Your load is close to maximum according to Lehigh's data: 42.5gr of H4350 for 2835MV from a 24" barrel. When I am loading for a rifle, I start low and work up until I hit max powder charge or the posted velocity corrected for barrel length. In your case about 2785MV from your 22" barrel. You are there. You can try a few other things to see if it is pressure or something else. You could back off a full grain of powder and seat your bullet to SAMMI length. If the pressure signs never return you know you were at or over max pressure and the little bit of carbon build up sent pressure way up. If pressure is still present, then it is something else. Try a different primer. CCI and Remingtons tend to not build up pressure as fast IME. When you do these tests, PLEASE wear eye protection...

Thanks for this advice. Makes sense, and being new I wasnt really confident on what I was seeing in terms of pressure signs.

Assuming I back off a 1/2 to 1 grain, would you recommend throwing the shells that blew primers out, or can I reload?

And in your experience does seating depth affect pressure, knowing I wasnt jambing lands?

 

[DagOtto]

Thanks Billy Goat,

Temperature was 50-55 F when I had problems and was in the 30s when I was developing the load.

All signs are pointing to me loading too close to the top. Then change in variables (25 degree temp increase, dirty chamber, etc,) pushed me over thr limit.

Ill clean those primer pockets and try to re prime and see what happens.

 

[Formidilosus]

Hi,
I was close to the top of acceptable pressure with this load. Will be dropping down 1/2 grain or so in future I think. Id typically been getting very slight ejector marks, and pretty flat primers, but not sticky bolts.

Ejector marks and flat primers.. and you’re unsure what the cause was?


The problem isn’t “barrel cleaning” as it never is. It’s loading hot as hell and having your bullets near, or touching the lands.

You play on the ragged edge and you will have all kinds of problems. You load smart, and they go away.

 

[DagOtto]

Thanks Mega,

Your note about being in the lands could very well be true. Id say out of all of the reloading metrics I was LEAST certain about measuring the distance to the lands, and was least confident in my consistence on OAL as I was loading. I had some variation in OAL that I attributed to not understanding how to adjust and lock the die, and have read that mono metal bullets set too deep can spike pressures. This might be as likely a culprit as lack of cleaning. I had ruled it out because all shots were cycled through the mag. (Hawkin Precision Hunter DBM) so I assumed if the cartridge could fit the mag than there is no way I was too far into the throat.

The gun hadnt been cleaned for 75 or so rounds prior to the problem. But when I borescoped it after that the throat area looked “wet” along with filthy with grit. I cleaned it last after an antelope hunt last fall when it was filled with dust from a 1 hour crawling stalk through a field. Now im wondering if I left cleaning fluid in the throat area as I struggle to get the chamber and throat really cleaned and then dried.


Damn, I hate variables!

 

[huntnful]

Ejector marks and flat primers.. and you’re unsure what the cause was?

It’s a learning curve lol. I’ve noticed a lot of new reloaders just go off bolt lift.

OP. Ejector marks and flat primers, especially on virgin brass, ESPECIALLY on virgin Lapua brass… is a major pressure sign. You’re way in pressure. That virgin hard Lapua case was just hiding the bolt lift pressure sign.

 

[DagOtto]

Hi Form,

Being new at loading Im learning I dont have a good feel for how far I am pushing into high pressure territory.

I was assuming that since ejector marks were slight (scuffs) and I wasnt getting any sticky bolts that I was still in a good zone.

No matter the nuanced reason for the primer failure (dirty chamber, temp, in the lands, or combo,) I think the lesson i learned is to not push it so far just for 50 or so FPS.

In your experience does shooting too-hot loads change your opinion on cleaning mattering? Or is your thought that my primer issue was mainly or entirely caused by other issues?

 

[DagOtto]

It’s a learning curve lol. I’ve noticed a lot of new reloaders just go off bolt lift.

OP. Ejector marks and flat primers, especially on virgin brass, ESPECIALLY on virgin Lapua brass… is a major pressure sign. You’re way in pressure. That virgin hard Lapua case was just hiding the bolt lift pressure sign.

Okay, thanks for this info!

 

[Megalodon]

I agree you're correct about this situation likely not being a carbon ring or a dirty barrel issue, but.....

The problem isn’t “barrel cleaning” as it never is. It’s loading hot as hell and having your bullets near, or touching the lands.

I'm so sick and tired of this. Seriously STFU, you are wrong. How many people have to shoot the same load and see a pressure spike with no velocity spike, then everything go back to normal after cleaning their barrel for you to see it's a factor?

If you're the only one saying this is non-existent, and everyone else who are experts in the industry say it is a thing how can you not see that you're wrong. I've never in all my years seen this level of hubris, and it's wildly off putting.

You may shoot more rounds than anyone else on this forum, and honestly it's kinda sad that is your only real claim to fame as far as I can tell, but it's a weak attempt at appealing to authority. Because like I said, it only holds on this form. Get outside of RS and there are people that shoot more rounds than you and have experienced and recognize that carbon rings are a thing.

 

[Formidilosus]

Hi Form,

Being new at loading Im learning I dont have a good feel for how far I am pushing into high pressure territory.

I said it with a grin. It’s all a learning curve, but there is no magic. There are lots of things in life that should be obvious that the “consensus” is often incorrect. Barrel cleaning is one.

I was assuming that since ejector marks were slight (scuffs) and I wasnt getting any sticky bolts that I was still in a good zone.

Slight ejector marks (slight) on tikkas when under book max is pretty common. But any other signs tell you to immediately stop and drop pressure.

No matter the nuanced reason for the primer failure (dirty chamber, temp, in the lands, or combo,) I think the lesson i learned is to not push it so far just for 50 or so FPS.

100%. People chase MV that greatly increases pressure, yet it does nothing for them on target. You need a buffer with your system (including ammo) for debris, rain/water, snow, etc. Running right up to pressure removes all leeway and you will have probes at some point.

In your experience does shooting too-hot loads change your opinion on cleaning mattering?

No, but only because “don’t use too hot loads”. Yes, if someone is running ammo at 70,000 plus PSI- EVERYTHING matters. Running your bullets in or right on the lands- EVERYTHING matters. Not full length resizing- EVERYTHING matters.


Doing any of those, and holy Pete- all of them, you WILL have issues in field guns eventually. The answer is “don’t do it”.

Or is your thought that my primer issue was mainly or entirely caused by other issues?

It’s caused by running your bullets at/in the lands, too hot of ammo, and having no leeway.

 

[Vern400]

Glad you picked up on what the guys are laying down for you. You'll be a lot happier if you find the next node down. I had a temperature related pressure issue a long time ago, and I intend to make it the last one.

Everybody talks about "oh, I developed a load at 50° and I shot at 80° and it was way too hot".

Yeah. Whatever. I was at a fun shoot with some friends and we put 40 milk jugs from 100 to 500 yards unmarked. Two shooters, he who kills more wins. At the end, one of the judges shouted" it's not over there's one standing past 400". I fired one last round and a blast came out of the bolt and the side gas vent. There was no opening the bolt.

As it turns out, you might develop loads at 50°, then leave your gun in the Sun, pop six or eight shells through it, have your ammo in a hot truck and all of a sudden you're shooting at 130°

Yeah. I did the FAFO. (RL15 is great but it runs like an Indy car. The hotter you push it the better it shoots but it'll redline in a heartbeat)

 

[TaperPin]

Time and time again guys post with pressure issues obviously cleaning related, yet the same tired old excuses that cleaning is never the answer, when obviously cleaning brought the pressures back down. It’s so predictable it’s kind of funny.

Some folks have good advice in some areas and bad advice in others. Imagine following the never clean method and being on the mountain when over pressures kick in and lock up your rifle. Simply blanking a primer can send the small disk of primer cup back into the bolt and jamb the firing pin, requiring a bolt disassembly.