WARNING - Murom Small Rifle primer blow outs

[MikeZZZ]

I recently bought a batch of Murom Small Rifle primers for use in my .222 Rem home loads. Having used Murom SR Competition primers before I had no hesitation in buying a batch of Murom SR primers when the Competition variety was no longer available.

HOWEVER - upon firing my reloads (PPU brass, 22gn Vit N133, 50gn VMax) I found approx 20% of the bases were blackened due to PRIMER BLOWOUT. I initially thought this was due to old brass with worn primer pockets - but on closer inspection, as I had the same problem with different head-stamp brass of different ages, I noticed that the cause of the blowback was the PRIMER had ruptured along its edge and the escaping gases had blackened and eroded the base of brass case and more worryingly when I cleaned the bolt face upon returning from the range I realised the escaping gases had also caused significant and visible erosion of the bolt face of my Sako 75 rifle. The ammunition still shot exceedingly well!

BE WARNED if you have any of this batch of Murom Small Rifle Primers - you could suffer the same fate as my Sako 75 bolt!

Does anyone know if the damage to the bolt face can be repaired and if you know of a gunsmith who can do this repair.

 

[MikeZZZ]

Here is the packaging of the offending primers.

 

[DK.260]

I have a bolt face with a similar appearance on my Surgeon 591......simillar situation and haven't used Moron primers for years as a result.

 

[Klenchblaize]

Who did you purchase the primers from? Pursue your claim for damages against the manufacturer via the retailer.

K

 

[25 Sharps]

This may be an issue of the wrong primer being used the standard primer are for low pressure, .22 hornet range, the competition are for higher pressure loads and have a thicker cup. Standard Murom rifle primers have a reputation for being very soft

They are not one and the same primer and had you followed the basic rule of working up a load again when changing a component you probably would have saved your boot face as you’d have noticed the primers flattening at lower charges.

 

[25 Sharps]

I have a bolt face with a similar appearance on my Surgeon 591......simillar situation and haven't used Moron primers for years as a result.

They are very good primers if you match the primer to the application

 

[jcampbellsmith]

MikeZZZ
How many rounds did you fire?
Regards
JCS

 

[Yorric]

One primer failure can burn a bolt face in my experience.
Ian

 

[308tikka]

luck suing... they were gray imports. Allegedly. Thats now been stopped.

the competition ones are pretty good though
Youre not far from HPS. Take it in and they will have a look. Might need a repair or new bolt face. Alternatively for expert knowledge, but farther away, go to Norman Clark in Rugby.

 

[25 Sharps]

Have a read of the article below by our very own @Laurie

Small Rifle Primer Performance in the 308 Palma case Pt.2 by Laurie Holland

Let’s look at SR primers. I tried a total of 15 from 10 manufacturers, with a 16th as the aforementioned follow-on which became available after the others were ‘done’. (Actually, this became 14 and 15th after one of the originals had to be withdrawn). In addition to the commonly available...

www.targetshooter.co.uk

the .222 needed a tougher primer than the REM 6.5 wasn’t tough enough hence the invention or the Remington 7.5 BR primer.

The original copper coloured sr primers from murom are as soft as the REM 6.5 (softer according to some sources). Forums are strewn with threads about this primer and people using it in applications it just can’t cope with.

 

[Foxyboy43]

Hmm. Definitely not good and your charge of N133 is just about halfway through Viht’s own data for 50 gns bullets so should not be an issue of this magnitude - in any case which is in reasonable condition particularly the primer pocket. Two questions for me:-
- are you sure the primer pockets were in good shape and up to the stress of reloading? and
- what did the primer box say i.e. did it specify calibre suitability or caution against other than hornet or what?
Providing you are certain that the primer pockets were good (pull a few from rounds loaded at the same time, gently deprime and check whether the cases will let you pick up an unfired primer by placing the case bottom over it and trying to get it into the pocket with gentle pressure. If the cases will pick up primers you are royally stuffed! However you will have redress against the RFD and/or the manufacturer if you can prove that the cases were indeed acceptable - including the pockets.
The damage to your bolt face howsoever caused is I suspect not repairable.

 

[JTO]

I'm using KVB-223 Competition Primers, Lot 6 - 17 with no problems. 22.1 Grs of n133 behind 80gr Amax and 23 grs behind 63gr Sierra Vaminter in a 223.
How are you seating the primers?

 

[C h r i s]

I've witnessed the same awful results with primer rupture on the Murom 50BMG primers, I can't afford to replace or repair my bolt faces so avoid now.

 

[MikeZZZ]

This may be an issue of the wrong primer being used the standard primer are for low pressure, .22 hornet range, the competition are for higher pressure loads and have a thicker cup. Standard Murom rifle primers have a reputation for being very soft

They are not one and the same primer and had you followed the basic rule of working up a load again when changing a component you probably would have saved your boot face as you’d have noticed the primers flattening at lower charges.

Have to disagree with you on the fundamental point that I purchased small rifle primers for use in a small rifle primer cartridge load that was a low /standard power load for the .222 Rem. If they were manufactured correctly as SR primers then they shouldn't be failing like this. The photos indicate no excessive primer flattening or any other high pressure signs. The charge was checked on a chrono in a test batch with no pressure or velocity deviations before I loaded the full batch.

 

[MikeZZZ]

MikeZZZ
How many rounds did you fire?
Regards
JCS

About 150 at the range before I cleaned the rifle and the bolt face. Failure rate was about 20-25%. Some had a hint of carbon around the primer, about 5% looked like the ones in the pictures.

 

[MikeZZZ]

Who did you purchase the primers from? Pursue your claim for damages against the manufacturer via the retailer.

K

I will be doing that tomorrow. I have already notified them.

 

[MikeZZZ]

luck suing... they were gray imports. Allegedly. Thats now been stopped.

the competition ones are pretty good though
Youre not far from HPS. Take it in and they will have a look. Might need a repair or new bolt face. Alternatively for expert knowledge, but farther away, go to Norman Clark in Rugby.

Agree with you about the Murom Comp primers - they worked very well in my loads. I guessed these would as well - how wrong I was! The Murom Comp primers are a golden colour whereas the Murom Standard primers were a copper/browny colour - obviously quite different material was used in their manufacture and it wasn't just Comp primers were exposed to higher quality control.

 

[MikeZZZ]

Have a read of the article below by our very own @Laurie

Small Rifle Primer Performance in the 308 Palma case Pt.2 by Laurie Holland

Let’s look at SR primers. I tried a total of 15 from 10 manufacturers, with a 16th as the aforementioned follow-on which became available after the others were ‘done’. (Actually, this became 14 and 15th after one of the originals had to be withdrawn). In addition to the commonly available...

www.targetshooter.co.uk

the .222 needed a tougher primer than the REM 6.5 wasn’t tough enough hence the invention or the Remington 7.5 BR primer.

The original copper coloured sr primers from murom are as soft as the REM 6.5 (softer according to some sources). Forums are strewn with threads about this primer and people using it in applications it just can’t cope with.

Wish I had your knowledge before I bought them!!!

 

[MikeZZZ]

I'm using KVB-223 Competition Primers, Lot 6 - 17 with no problems. 22.1 Grs of n133 behind 80gr Amax and 23 grs behind 63gr Sierra Vaminter in a 223.
How are you seating the primers?

I used those with no ill effects bought from HPS - they were very good in fact. I seat my primers using an RCBS hand primer tool and check seating depth after seating by finger rub.

 

[MikeZZZ]

Hmm. Definitely not good and your charge of N133 is just about halfway through Viht’s own data for 50 gns bullets so should not be an issue of this magnitude - in any case which is in reasonable condition particularly the primer pocket. Two questions for me:-
- are you sure the primer pockets were in good shape and up to the stress of reloading? and
- what did the primer box say i.e. did it specify calibre suitability or caution against other than hornet or what?
Providing you are certain that the primer pockets were good (pull a few from rounds loaded at the same time, gently deprime and check whether the cases will let you pick up an unfired primer by placing the case bottom over it and trying to get it into the pocket with gentle pressure. If the cases will pick up primers you are royally stuffed! However you will have redress against the RFD and/or the manufacturer if you can prove that the cases were indeed acceptable - including the pockets.
The damage to your bolt face howsoever caused is I suspect not repairable.

Yes my primer pockets were all in good shape and more than unto the loads I am using in the homeloads. You can see in the pictures no blackening or erosion in the walls of the pocket. I have checked the offending cartridge primer pockets and they are definitely not loose - you cannot seat a new primer in them without using a priming tool. The primer box had no warnings over intended use - see pictures.