Pierced primers: Murom small rifle magnums

[Catch-22]

I've just tried the Murom small magnum primers in my 6.5x47 and experienced some odd things.

 

Reason for trying was I've found CCI250 gave me inconsistent ES. The Muroms however were excellent, a total ES of 8fps over 15 rounds!

 

But I did run into some issues with them. I got 3 pierced primers and 2 light strikes. No signs of over pressure, confirmed by no cratering, primer flow, no ejector marks and the magneto speed velocities were normal. I was using exactly the same charge, case and bullet as with my CCI250 and I've never had a problem with them.

 

I wonder if seating depth in the primer pockets is the issue. Seems some Murom seat deeper than others, causing light strikes, and maybe the pierced primers were due to not being seated quite deep enough?! Again never had this issue with CCI250 in hundreds of reloads.

 

Anyone else had similar problems with the Muroms?

[Brillo]

Categorically no. I've shot, maybe 2000 rounds with Murom KVB 223 primers and no problems whatsoever. I'm not going back to CII BR4s

[Grum87]

When I was running Muroms(KVB7 large rifle's), it was recommended to seat them VERY firmly. The reason being that you really need to seat/press the primer cup flat against the anvil to get them to light up reliably. This could be the source of your light strikes. If you're not seating them hard, the priming compound doesn't get enough of a shock to go off between the primer cup and the anvil.

 

Peirced primers is a different story though....

[Catch-22]

@

Categorically no. I've shot, maybe 2000 rounds with Murom KVB 223 primers and no problems whatsoever. I'm not going back to CII BR4s

Brillo - do you use the KVB 223 or 223M? I'm using the 223M.

 

When I was running Muroms(KVB7 large rifle's), it was recommended to seat them VERY firmly. The reason being that you really need to seat/press the primer cup flat against the anvil to get them to light up reliably. This could be the source of your light strikes. If you're not seating them hard, the priming compound doesn't get enough of a shock to go off between the primer cup and the anvil.

 

Peirced primers is a different story though....

Grum87 - interesting. I do suspect seating depth of the primers is the cause of the issue. It seems the Murom's almost seat too deeply in some instances, like they're shorter in height than say the CCI250, though I've not measured them so can't prove it. But some do seem noticibly deeper in the primer pocket. The CCI's were always consistent in depth, maybe the cup is just a little higher/longer?!?

 

I think I just need to be super careful with seating these primers, but they definitely seem worth sticking with because of the performance they give.

 

Thanks for the advice/feedback.

[Grum87]

The KVB7's shot superbly for me, not a single issue and ES was half that of Fed210m. Can't get them locally just now though, BR2's provide ever so slightly better ES, but not sure its worth twice the price.

[baldie]

If you've had 3 pierced primers, you will get more light strikes. Your bolt needs stripping and flushing out. The piece of primer which detaches when pierced, only ever goes one place....down the firing pin hole.

[Catch-22]

That's true - very good point. A previous rifle I had got a pierced primer once and I remember having to strip the bolt which solved the issue.

 

Many thanks Baldie!

[gunner]

Although iv never had this issue , im about to try these instead of 205m , if this is a seating depth issue hopefully i shouldn't have a problem seating with consistency iv now used a k&m seater for a couple of years ,, i still have the old rcbs type but god im never going back to the 'guess' style one's . The k&m has a dial so i know every one is seated 2thou under , if you can get one ( or one similar ) by god its worth it . Apologies i know this aint really a help on the primer issue . I post back if i get any duff murons . Atb

[Re-Pete]

I've never had a piercing or FTF with KVB-223M's, and I've used 2000 of them so far in .223, 6BR, 6.5x47, and 308, with some stiff loads.

Recently bought another 10,000..........

 

RePete

[Catch-22]

Hmm, interesting. Many thanks to all who replied.

I've got 5000 of them and I'm very impressed with the lower ES I'm getting. I'll just keep an eye on seating them as I'm sure that's the issue - maybe I just didn't seat those few that pierced deep enough?!

 

Cheers

[bradders]

The M's aren't Magnum, but they have a thicker cup to withstand Magnum type pressures

I'd be checking the tip of your firing pin for any sharpness or erosion from those piercings, you may end up needing a new one

 

What rifle action are you using?

[Re-Pete]

Check the firing pin tip with a good magnifier...........I had one of the Tikkas with what looked like a flake chipped off the side of the point.

This flat had sharp edges. Careful wipe with a bit of Arkansas stone smoothed it away.

 

RePete

[Catch-22]

Thanks chaps. I did strip the bolt down and gave it a good clean and dab of grease but didn't notice any burrs or sharp edges.

 

Rifle is a Tikka 595 rebarrelled in 6.5x47L.

 

Again, not an issue I've experienced in hundreds of rounds with the CCI250, hence my original question about the cup thickness of the Murom.

I did measure the cup height of both CCI 250 and the Muroms and they were essentially identical but I wonder if the 3 that pierced just weren't seated deep enough?!

 

@Bradders: my kvb 223m Muroms do say "small rifle magnum primers". Are they not magnums then, just a thicker cup than the kvb 223's??

 

Many thanks again for the advice!

[gbal]

Catch, This isn't a new thing- Laurie (Holland ,here) did a post reply on UK Full Bore UK,"Morom primers and 223",22 Sept 2015.

Reports of problems,and difffernt 'batches' of Murom KVB-223 with different colour primer-some of which were problematic.

 

As Laurie pointed out,there is some confusion generally-early/standard SR primers like CCI 400,Rem 61/2,Fed 205- were designed for 22 Hornet and similar sub 50,000psi cartridges and are .020" (222 Rem on the limit for these....

 

Later SRs like Fed 205M (Match not Magnum?) are .0225",and all Magnums and BRs are .025" (and usually have somewhat harder alloy).

223 Exceeds 50,000 so needs Magnum/BR grades

Much 5.56 likewise runs higher pressures.

 

Laurie's advice ws reported as also posted on CSR site....

 

All this isn't helped by careless reference to primers. Eg Rem SR (well,61/2 or 7/2 BR?)...and Muroms are especially loosely refered to, it seems....

 

Just needs some care and authoritative guidance (ie Laurie).

 

 

 

gbal

[Catch-22]

Catch, This isn't a new thing- Laurie (Holland ,here) did a post reply on UK Full Bore UK,"Morom primers and 223",22 Sept 2015.

Reports of problems,and difffernt 'batches' of Murom KVB-223 with different colour primer-some of which were problematic.

As Laurie pointed out,there is some confusion generally-early/standard SR primers like ICI 400,REm61/2 Fed 05- were designed for 22 Hornet and similar sub 50,000psi cartridges and are .020" (222 Rem on the limit.

Later SRs like Fed 205M (Match not Magnum?) are .0225",and all Magnums and BRs are .025" (and usually have somewhat harder alloy).

223 Exceeds 50,000 so needs Magnum/BR grades

Much 5.56 likewise runs higher pressures.

Laurie's advice ws reported as also posted on CSR site....

All this isn't helped by careless reference to primers. Eg Rem SR (well,61/2 or 7/2 BR?)...and Muroms are especially loosely refered to, it seems....

Just needs some care and authoritative guidance (ie Laurie).

gbal

Hi gbal,

Thanks for reference to Laurie's post. I've read that but they're discussing problems with the regular kvb 233 primers, the non-magnum ones. Thing is I'm using the copper coloured kvb 223m magnums, with the thicker cup, so in theory it shouldn't be a problem.

Out of 50, I had 3 pierced and 2 light strike, though I agree with Baldie's assessment that the light strikes were more than likely due to the bolt/firing pin needing cleaning out after the 1st pierced primer (which it did and is now fine).

I'll double check for burrs on ththe firing pin, as per one helpful suggestion above, but otherwise all I can think of is to possibly be conscious of is how deep the primers need to be seated. Again, maybe it was user error but just wanted to see if anyone else had the same issues with the kvb 223m magnums.

Thanks!

[Catch-22]

As an update, I checked my firing pin very carefully and neither saw or felt any burrs, chips or anything which would cause the primers to be pierced.

I can only assume the 3 pierced primers were down to not seating them deep enough in the pocket.

 

Many thanks to all who offered up advice and help.

[DaveT]

I got what I thought were light strikes the first time I used Murom large rifle primers in place of CCI BR2s.

 

If you measure unfired examples of both brands they are the same depth.

 

If you measure the fired cups the Muroms are .007" shallower than CCIs.

 

I had been seating the Muroms as per thousands of CCIs previously only to get an , apparently, light strike first time.......lift and close the bolt and fire again and all is well!

 

The first attemot served to seat the Muroms fully such that the 2nd set them off just fine!

 

I now seat Muroms to what looks like excessive depth and they fire reliably.

 

I have not used my first batch of small rifle Muroms yet but worry that they are NOT suitable for my AR15 as per reported issues....I have 1000 designated mv223 are these going to pierce?

[Re-Pete]

If they have KVB-223M or Magnum on the box, all should be well..................

 

RePete

[DaveT]

Oops....no M anywhere...looks like I have 1000 useless primers!

[Laurie]

Oops....no M anywhere...looks like I have 1000 useless primers!

 

When you said 'mv223' in your earlier post, did you mean SR223, or Small Rifle 223? If so, they are the KVB-223M 'magnum' SR primer and an excellent and tough performer, a current favourite in Wolf or Tula packaging with the US High-Power XTC crowd. This (bronze colour) primer is as 'tough' as the older 'silver' (nickel plated) SR Magnum (KVB-5,56M) but is a little 'hotter' and better suited to ball powders in the 223 Rem.

 

If they are plain 'Standard Small Rifle' (KVB-223), yes they are soft. They used to be a deep copper colour, but I'm told they are now also 'brass' finish.

 

Russian SR primer types / designations is a real mess with four company names and several OEM product designations. It is the last of these (the KVB codes) that are the ones to know ..... but amazingly, they're neither printed on the 100 ct sleeve or on the 1,000 ct. 10 X tray box, only on the 5,000 ct cardboard packaging 'outer' (which gunshop owners and assistants usually discard on unpacking the product).

 

Obviously some things haven't changed that much in Russia from the good old days of Soviet efficiency.

[DaveT]

Laurie

 

Many thanks for the detailed info...you are a goldmine!

 

I will double check the packaging.

 

I wonder how many gun shops are actually aware of the issue and are unsuspectingly supplying unsuitable product?

[DaveT]

Laurie

 

Checked....they are KVB-223 and copper coloured....bugger!

 

So these are unsuitable for AR15 and anything which runs pressures over about 55,000 psi?

[Laurie]

When I used the old PMC branded version of this primer years back in an SGC SSR-15, they'd 'blank' in quite modest 69gn loads, 55,000 psi if that even. In a conventional turnbolt like the Remy 700 in 223, they may or may not be fine depending on the firing pin tip's fit in the bolt-face. if slack, they'll crater badly.

 

They're excellent for lower pressure numbers such as the Hornet and .222 Rem, and actually work very well indeed in high-pressure applications with a good quality custom action with a small diameter firing pin and tight fit in its bolt aperture. I've seen them used in hot FTR loads in 308 Palma brass in such actions, although few competitors appreciate just how good a primer this can be for such applications. (A mild and very consistent performer.) They do come out of the rifle as flat as pancakes though and people sometimes (wrongly) get in a tizz about excessive pressures.

 

If you weren't 100 miles away, I'd buy them off you.

[furrybean]

When I used the old PMC branded version of this primer years back in an SGC SSR-15, they'd 'blank' in quite modest 69gn loads, 55,000 psi if that even. In a conventional turnbolt like the Remy 700 in 223, they may or may not be fine depending on the firing pin tip's fit in the bolt-face. if slack, they'll crater badly.

 

They're excellent for lower pressure numbers such as the Hornet and .222 Rem, and actually work very well indeed in high-pressure applications with a good quality custom action with a small diameter firing pin and tight fit in its bolt aperture. I've seen them used in hot FTR loads in 308 Palma brass in such actions, although few competitors appreciate just how good a primer this can be for such applications. (A mild and very consistent performer.) They do come out of the rifle as flat as pancakes though and people sometimes (wrongly) get in a tizz about excessive pressures.

 

If you weren't 100 miles away, I'd buy them off you.

 

Ssshhh Laurie

 

Dont tell everyone!

[DaveT]

When I used the old PMC branded version of this primer years back in an SGC SSR-15, they'd 'blank' in quite modest 69gn loads, 55,000 psi if that even. In a conventional turnbolt like the Remy 700 in 223, they may or may not be fine depending on the firing pin tip's fit in the bolt-face. if slack, they'll crater badly.

 

They're excellent for lower pressure numbers such as the Hornet and .222 Rem, and actually work very well indeed in high-pressure applications with a good quality custom action with a small diameter firing pin and tight fit in its bolt aperture. I've seen them used in hot FTR loads in 308 Palma brass in such actions, although few competitors appreciate just how good a primer this can be for such applications. (A mild and very consistent performer.) They do come out of the rifle as flat as pancakes though and people sometimes (wrongly) get in a tizz about excessive pressures.

 

If you weren't 100 miles away, I'd buy them off you.

One day I will get up to Diggle and they will be yours gratis!......thanks for your advice.