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Re-Pete

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Having bought some KVB-223M primers, I measured the cup thickness and compared them with Rem 7.5, BR4, and KVB-223.

 

I potted them in some resin and ground them down to make a crude microsection......see attached pic.

 

For what it's worth, here are the results:

 

A= Rem7.5 Thickness of cup where the firing pin hits it: 0.68 mm
B= KVB-223M 0.63
C= BR4 0.68
D= KVB-223 0.48
I wasn't too sure about the 223M's, but after measuring them, I tried them with a stiffish load (155 Scenar at 3050fps) in 308 Palma cases, and they were fine.
At £21/1000, they're a no-brainer.post-11477-0-87845300-1476894218.jpg
Re-Pete
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KVB7's (LR) shot very very well for me, half the ES of 210M's.

 

Good primers.

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RePete,

 

Nice bit of analysis, thank you for sharing.

 

Re. the 'Russian primers' I was switched onto these about 10 years ago when they were sold as part of the PMC line of products (by a bloke called Tubb ) and have used them in quite a few different cartridges with good results.

 

One cartridge I've not yet played with though is the 6.5x47 as the CCI 450's have been 'it' from day one - has anyone used the Muron's in this case?

 

Brgds Terry

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RePete,

Nice bit of analysis, thank you for sharing.

Re. the 'Russian primers' I was switched onto these about 10 years ago when they were sold as part of the PMC line of products (by a bloke called Tubb ) and have used them in quite a few different cartridges with good results.

One cartridge I've not yet played with though is the 6.5x47 as the CCI 450's have been 'it' from day one - has anyone used the Muron's in this case?

Brgds Terry

Yes Terry. I got a few to play with and I'm astonished at the result. I normally use BR-4s and with my 139 Berger VLDs there is no difference in performance.
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Laurie (Holland) did his usual decent sample/design test of primers some years ago-see Target Shooter/google,and the 'Muroms" 7s did rather well,as I recall,a bit better than Fed 210,but the same as 210M-but there was not a huge anount in it,unless you truely believe that 10fps is more important than wind error.Any differences that MIGHT have been shown statistically,are unlikely to have field significance-but there are other criteria.And of course,manufacture can change....but it seems the Muroms remain very decent primers as far as has been tested....how is the £ against the rouble,these days?

 

gbal

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  • 3 weeks later...

More on primers..............I measured the following:

 

KVB-223 Std, (the copper coloured type Lot 1-11 that were available initially) 0.020"

Federal 205 SR 0.022"

Sellier & Bellot SP 0.015"

 

Anyone who's used both the original copper plated std KVB's and the latest std brass coloured version will know that the later type are less robust, although the thickness is almost identical.

However, the KVB-223 Magnum's are in a different league altogether.............I've found them to be very consistent, and hard enough to be a very good substitute for BR4's at almost 1/3rd of the price.

 

Repete

 

RePete

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I've now had the opportunity to try the KVB-223 Magnums, and IMHO, they're as good as BR4's..........very consistent and no excessive flattening, cratering or piercing.

 

Repete

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Er sorry about that......having a bit of finger trouble this morning.........two windows open.................

 

Repete

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I've now had the opportunity to try the KVB-223 Magnums, and IMHO, they're as good as BR4's..........very consistent and no excessive flattening, cratering or piercing.

 

Repete

 

I've repeated the exercise that George (Gbal) mentions but with SR primers (14 varieties) in Lapua Palma 308 Win brass and the KVB-223 was a star performer. The overall 'winner' (in terms of smallest ES/SD) was a 'cheapo' though, the Brazilian CBC Magtech 7 1/2 as stocked and sold by Bradders of UKV fame. It is a bit 'softer' though cup-wise than the CCI-450 / BR4, but not enough to be a liability. (A few models, not unexpectedly, were so soft as to be a liability, and in one case the test had to be terminated within five rounds on the second occurrence of primer 'blanking' with a standard pressure load.)

 

Overall, the SR primers were MUCH more consistent and with far less performance difference between models than their LR big brothers also in 308 Win.

 

It'll be written up soon in Target Shooter online.

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It'll be written up soon in Target Shooter online.

I look forward to that Laurie as I'm just about to move over to Palma cases with a new barrel.

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  • 4 months later...

 

I've repeated the exercise that George (Gbal) mentions but with SR primers (14 varieties) in Lapua Palma 308 Win brass and the KVB-223 was a star performer. The overall 'winner' (in terms of smallest ES/SD) was a 'cheapo' though, the Brazilian CBC Magtech 7 1/2 as stocked and sold by Bradders of UKV fame. It is a bit 'softer' though cup-wise than the CCI-450 / BR4, but not enough to be a liability. (A few models, not unexpectedly, were so soft as to be a liability, and in one case the test had to be terminated within five rounds on the second occurrence of primer 'blanking' with a standard pressure load.)

 

Overall, the SR primers were MUCH more consistent and with far less performance difference between models than their LR big brothers also in 308 Win.

 

It'll be written up soon in Target Shooter online.

 

Laurie, do you mind if you clarify that the KVB-223 was a star performer and not the KVB-223M?

 

Ive aquired 300 to try as Im having issues with my BR4's

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The old Russian PMC SRM was my primer of choice for 223 with 90s, and is still a top performer there. It combined the hardest / toughest cup with small ES/SD values and good groups. I presume we'd now call this model the KVB-223M, but am not 100% sure as Murom nomenclature is rarely straightforward IME. It proved 'milder' in the 223 compared to the BR4 and the latter wouldn't allow loads to be tuned as well.

 

In 308 Win 'Palma', the PMC SRM was a disappointment and gave far poorer results than the BR4, also poorer performance than from the old basic PMC 223 SR with the very soft copper cups albeit it barely avoided serious cratering / blanking, but the recently arrived Murom SR223 proved better than either.

 

So, as suspected, primer performance is likely not an absolute across all cartridges, but has varying suitability according to application, maybe even individual powder grades. Who knows, maybe even by primer production lot too? The good news is that there is much less performance variance across SR models than I found in LR.

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Thanks for the reply Laurie.

 

I think I've got one of the stinking batch of BR4's with a crazy number of misfires as seen in my last shoot. I contacted CCI and was told it was either contamination or poor primer strike which both have been discounted so I'm on the lookout for a new source.

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I'm now using the KVB-223 Magnum primers across the board.....308 (Palma), 6.5x47, 6BR, and 223. Attached is a pic from a recent load test session with a 6.5x47 at 300 yds.

This was the best result, and a follow up at a windy 600yds the week after confirmed it.post-11477-0-99801900-1490858812_thumb.jpg

After the first shot, I adjusted the windage, took three more shots and made the mistake of checking through the spotting scope............shot five was the result, an inch away.

I really wish I could get near this every time!!

 

RePete

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Nice shooting!

I use KVB223 in my 308 Palma and 6.5x47L and have abandoned using BR-4s.

I've yet to try the magnum primers. What's the real world difference?

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Accurate Shooter bulletin today 30th has a heads up on primers-and gives the link to Allan James "Mysteries and Misconceptions of the all important primer " : (he was tech manager of CCI/Speer) This is an easy read heads up on what primers are...and some of the myths that have grown up about them.....

 

If you want to know which primer(s) to try for your cartridge,our very own Laurie Holland has done it/tested properly/reported...back threads-and no doubt current/future ones on here and articles in Target Shooter (online available). It really does not get any better for UK shooters....and the extra small ,small rifle flash hole variation is covered!

 

gbal

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Great thread guys.

 

Ive got thousands of BR4's but got loads of ftf on the last f class shoot which was really offputting for me and my fellow competitors!

 

This batch was B09X22 if anyone else has similar experience

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