.308 Bolt Face Cases with Small Rifle Primers Question

[John MH]

I only have limited experience with small rifle primers in .308 Bolt Face size cases and wonder if people have issues with reliable ignition using standard small rifle primers. I had a misfire yesterday with new Peterson SRP 6XC cases, on pulling the bullet the powder was scorched but did not burn, I was using Murom KVB-223 primers. What primers are those shooting 6.5 Creedmoor with Lapua SRP brass using?

[AJW7088]

Hello John,

My lad is using CCI 400s with his Rem 700 PCR in 6.5 Creedmoor, with no problems.

Adrian

[Brushy]

CCI br4s in my 6.5 creed with srp Lapua brass. 

Work great so far...

[Catch-22]

I shoot a 6.5x47 in my Defiance Mutant XL switch barrel action. 

Admittedly I specified the .308 bolt came with a small firing pin hole & pin, but I don’t think that’s your issue.

I use Murom KVB-223 MAGNUM... not the standard 223 ‘mild’ version. 

The only issue I’ve had was a couple of delayed ignition rounds when I was conducting an OCW with RS52. For some reason, I had a few rounds that went ‘click, pop...wait...BANG’. 

I’ve never had any issues with any other powder, before or since (used N140, VARGET, RS62 in 6.5x47 guise) and (RAMSHOT Magnum, RS80 in .338NM).

I would suggest it is either the primer (not being ‘hot’ enough - I believe Laurie’s testing showed the Murom 223 being both mild and having a thin cup) or its the powder, or that particular primer isn’t best suited to that particular powder, as I think was the case when I tried KVB-223M with RS52.

[John MH]

I was using Elcho 17 (RS62 & RL17 equivalent/same), 39.5 grains and a 115 grain DTAC. Might try and get some KVB-223M primers to try but will have to switch to BR4 from now.

[rhhudson]

I use Cci 450 in my 6.5x47 

They are magnum  primers with a thicker cup. Never had any ignition problems to date. 

[Brillo]

Me and my colleagues in a FTR team use Murom KVB 223 primers and have for a long time we’ve never experienced that problem and between us I estimate 10000 shots.

The magnum  primer isn’t hotter, it simply has a thicker cup. I am reliably informed that this is correct from a main importer who was told this directly by Murom.

[Catch-22]

1 hour ago, Brillo said:

Me and my colleagues in a FTR team use Murom KVB 223 primers and have for a long time we’ve never experienced that problem and between us I estimate 10000 shots.

The magnum  primer isn’t hotter, it simply has a thicker cup. I am reliably informed that this is correct from a main importer who was told this directly by Murom.

Interesting. I know the importer too but don’t know if he’s conducted any primary research into the differences himself?

All I can go on is Laurie’s informative, tireless and generous research. Quoting Target Shooter Magazine;

http://www.targetshooter.co.uk/?p=2662

“...The cardboard ‘outer’ marked with the useful factory product code had been ditched by the retailer unfortunately but I’m pretty sure this is the Murom KVB-223M, a thick cup, tough ‘magnum’ model that is slightly ‘hotter’ than the older KVB-5,56M ‘magnum’.

Murom KVB-223M 2838 fps average MV; 15 fps E.S.; 3.8 fps SD.

An excellent result that betters that of the previous test ‘winner’, the CBC Magtech model. The three groups averaged just over the half-inch, so a good result here too. The test was run exactly as for the others, so the mid-string restart shot was examined and, yet again, (the 10th occurrence) it fell below the rest of the spread – by 4 fps this time. Knocking that reading off and redoing the calculations gives a revised:

2838 fps average MV; 11 fps E.S.; 3.3 fps S.D”

Compare the above to his results to the standard Murom KVB-223;

2,815 fps average MV; 18 fps E.S.; 5 fps S.D.”

 

So it does appear that KVB-223M is indeed ‘hotter’ than the regular KVB-223, in addition to having a thicker cup.

BUT...my point in this instance is more that the primer makeup itself may not be suitable for this given cartridge (size, dimensions) with the given powder used. I don’t know, it might be the size of kernel, the type of powder used, whether the kernels were compressed or given the shape of the case internals, was there too little (or too much) air space in there to reliably ignite? Dunno...a lot of variables.

I would still suggest trying a different primer, regardless of whether it’s a magnum or not, just a change might fair better with the given powder. Worth a try to see?!?

[Catch-22]

2 hours ago, John MH said:

I was using Elcho 17 (RS62 & RL17 equivalent/same), 39.5 grains and a 115 grain DTAC. Might try and get some KVB-223M primers to try but will have to switch to BR4 from now.

Just FYI, RS60 is the same as Elcho 17 & Alliant RL17.

RS62 is a single base powder...not the same.

[John MH]

Ok, thanks for the clarification.

[bradders]

20 hours ago, Catch-22 said:

“...The cardboard ‘outer’ marked with the useful factory product code had been ditched by the retailer unfortunately but I’m pretty sure this is the Murom KVB-223M, a thick cup, tough ‘magnum’ model that is slightly ‘hotter’ than the older KVB-5,56M ‘magnum

That wouldn't be because they’re still on the embargo/banned/ prohibited list for Russian arms and ammunition by any chance, would it?

[Catch-22]

Don’t ask me guv’ 🙈🙉🙊

[TJC]

CCI 450 Small Rifle Magnum Primer

[TC]

On 8/4/2019 at 5:50 PM, John MH said:

I was using Elcho 17 (RS62 & RL17 equivalent/same), 39.5 grains and a 115 grain DTAC. Might try and get some KVB-223M primers to try but will have to switch to BR4 from now.

John,

I’ve used BR4 under 48 grains of RL17 in SRP .308 without issue.

Tony

 

[John MH]

Thanks, BR4 it is then.

 

[Bangbangman]

I've used BR4 and CCI450 for RS52 in 6.5x47 (settled on the CCI450)