I went to the range yesterday with my Bergara MG Lite 7mm PRC 22" Cure Barrel, Veracity PH Burris scope, and a Banish 30 Suppressor attached.
My groups were sub 1MOA on paper and once I sighted in the rifle I was easily on target. Then I had a primer blowout which was the only wild flyer of the day. I probably flinched a little on that shot.
Using Factory batch #80711 LOT# 3231663 - Hornady Match 7 mm PRC 180gr ELD bullets - I experienced a primer blowout indicating an overpressure situation. No other indications of overpressure were observed. Only 1 out of 40 rounds I shot did this but it was a little surprising.
I did contact Hornady to let them know about this overpressure situation.
Any one else experience factory load overpressure.
I have noticed flattened primers and ejector marks on hornady 7 prc brass compared to Peterson brass when all things else are equal. Not a large sample size, but it was noticeable.
I’m pretty sure Hornady is really pushing their factory loads to the limit for marketing. Trying to replicate the specs of that ammo in GRT led to this (using N570), its not surprising that people would get overpressure issues especially in warm weather:
This rifle is brand new – and I have only shot 40 rounds of Match through it – and the blowout of the primer occurred around the 10th to 12th shot.
So, what Hornady is telling me, is their Match ammo fouled my barrel enough after only so few of shots that it created a carbon ring which caused an overpressure to blow out the primer - breaking it into two pieces.
Hornady wrote “ I looked up that LOT# and it was loaded well below SAAMI max pressure.”
I call BS - according to Hornady’s own load data, to achieve advertised Muzzle Velocity of 2975fps the MATCH load would have to exceed their published maximum load data for the 180 gr. ELD – i.e. 67.0 gr. of RL26 or 69.0 gr. of RL25 = 2950fps.
One thing not being talked about with 7 prc is how fast a carbon ring can form. It can be in as few as 40 shots, which is kinda crazy. It really requires a lot of cleaning.
I know in some recent post the idea of a new video regarding cleaning came up and you said you’d be interested in pursuing that. If and when you do, please be sure if you can to show exactly what a carbon ring looks like, as well as how you prefer to attack it.
I keep hearing about it and reading about it but never have seen anything definitive in terms of pictures or video.
Thanks
Oh,
And Gunwerks not too long ago did a a YouTube video about cleaning. They said since they’ve been shooting more and more suppressed they found that they’ve needed to clean a lot more often than prior. And even more so with a higher caliber, more Magnum cartridge. Don’t know if that’s applicable in the Op’s situation.
I will use my endoscope to inspect the barrel for fouling.
I had heard RL26 was really dirty which is the powder I read they used on original ammo. I am not positive how long before, but this ammo had been on the shelf since January 2024 when I purchased it. So I think it is a good chance it is the old load with RL26.
Regardless, the max load for 180 grain bullets use RL26 and RL25 so I will check how much fouling and if there is a carbon ring.
Yep, suppressors are known to create carbon rings and it is probably reasonable that with a larger round, pushing more powder, that the carbon can accumulate faster than in smaller rounds. Go on youtube and watch the Barbour Creek “don’t overclean your rifle” video. They address carbon buildup from suppressors specifically.
good luck.
The Barbour Creek team covers some things from a different angle than most of the gun community does. That can be attributed, ( I think) to their lead instructor and his background; pretty no nonsense, practical applications, backed up by thousand and thousands of rounds down range and years of practical experience behind a weapon.
Glad it helped.
Yeah same thing happened with my turdy turdy 10 gauge side by side tomahawk with cruise control and the photon phazer banana clip, radioactive interswamp scud buster , turdy thousand gigwatt deer shiner/ cigarette lighter in the butt stock.
Just watch the video yesterday on YouTube from the reloading Weatherby channel. He’s going to send his 7PRC back to the factory as it’s not accurate and shooting much slower than it should be
He made an interesting comment I have not heard before. He said many other people had sent him messages and emails with their load data for their 7PRC which gave velocities that were what one expects from this cartridge. However he stated that every single one of them was at least two if not three grains over Maximum recommended load for that particular powder.
I just bought a bore scope so no pics yet. I have about 80 rounds through a Proof barrel and am not seeing any signs of over pressure. Shooting with a can. Shooting H match, eldx, outfitter and federal premium.
Getting 2950 in 22 inch barrel for 160 gr CX. Sub moa groups at 200 yds with CX. Not as good for the others.
So watching Little Crow Works today.
He said Hodgdon told him the top causes for carbon rings are:
supressors. by far the largest contributor
overbore
high humidity
For my 7PRC I use a Banish 30 in Oregon where it has rained 6 or 7 inches the last couple weeks.
At least its not a 28 Nosler for strike 3.
Of course I wonder why a can would cause more ring. I do not understand the physics or chemistry of it. Do cans increase back pressure even if that is the cause of a carbon ring?
Yes, suppressors do increase back pressure. This typically doesn’t come into play for most bolt gun shooters. However, it can become a big issue with a gas gun shooter. Changing the pressure of the gas system that drives the gun / action can lead to significant issues with gas operation and gun cycling.
Because of that, there is an entire line of suppressors which are designed to have low back pressure, and they are often referred to as flow through technology or something like that. Most of their ads will be geared towards the AR crowd.
If bolt gun shooters start getting concerned about carbon rings and back pressure maybe they will take off a bit more in terms of popularity. There’s a downside to the low back pressure suppressors, they don’t quiet as well as a regular suppressor.
