Load development

[n8ess]

Thanks for the info, l haven’t heard of Murom KVB-223m primers before? I have just purchased 6.5x47 & 22-250 Blaser with 22” match barrels so trying to work up some loads. I did think your loads were hot until l read about you coating them.

Saying  that I have a Borden Alpine in 6br and l run that above the recommended limits with no pressure signs. 
 

Can l ask what determines how often you coat your barrel and does this affect your cleaning routine?

[VarmLR]

Just don't mix up KVB 223's with the 223M versions!  Despite calling them the "KVB223" imho these are unsuitable for chamber pressures in 223, and in SR 6.5x47 and 6.5CM.  Cup thickness for the KVB-223 is 0.020" and for the 223M is 0.025" but AFAIK the charge type/mass is the same so they're not a "hot" variety.

I found out at my cost not to use .02" cup primers in my 223 where I experienced some blown primers and gas-cut bolt faces on charges that were within acceptable published limits.  The SR brass for 6.5's should use the thicker Magnum moniker primers, such as CCI450 and KVB-223M to reduce risks of blowing primers, especially when loading "hot".

 

 

[Re-Pete]

If you type "primers" in the search box, you'll find more info than you can shake a stick at..............

Pete

[VarmLR]

Laurie also wrote some very informative articles on both LR and SR comparisons published in accurateshooter.com and targetshooter.co.uk

[Catch-22]

8 hours ago, Re-Pete said:

I get the same MV with the same load, but using RS 50 powder in my 6.5x47.

Around 2900-2950 fps seems comfortable for the 6.5x47 and it's certainly accurate.

Pete

Yeah, I think this is a real accuracy node.

I remember reading an excellent article by Zak Smith (one of the early founders of practical precision shooting comps) who had his AI-AW chambered in a 25” barrel in the then very new 6.5x47.

He turned in many good loads with various bullets but the pick of the lot was a 123gn Scenar at around 2930fps.

So it would seem the 2920-2950fps harmonic node is just about the sweet spot for 123gn class bullets in a 6.5x47...regardless of powder and primer used.

[Catch-22]

9 hours ago, n8ess said:

Thanks for the info, l haven’t heard of Murom KVB-223m primers before? I have just purchased 6.5x47 & 22-250 Blaser with 22” match barrels so trying to work up some loads. I did think your loads were hot until l read about you coating them.

Saying  that I have a Borden Alpine in 6br and l run that above the recommended limits with no pressure signs. 
 

Can l ask what determines how often you coat your barrel and does this affect your cleaning routine?

Yes the KVB-223m is a good primer. But there are many others too. As VarmLR notes, Laurie Holland has done some Stirling primer tests and makes some brilliant recommendations.

My loads are hot, in that they are over book max. But again they exhibit zero pressure signs in my rifle - no cratering, flattening of primers, no sticky bolt, no ejector marks, no hard extraction and no real growth of the web. F/L sizing each time is easy...no issues.

I wouldn’t expect you to get anywhere near that velocity in a 22” tube. Possibly around 2750fps I’d think. But I have no doubt you’ll find a very accurate node very quickly. I’ve found the 6.5x47 to be one of the most easy to tune and forgiving calibre’s out there!

Yes coating does mean I need to go around 1 full grain higher than I coated bullets to obtain the same velocity.

Coating the barrel, I use a 95% mix of 99% Isopropyl Alcohol to 5% mix of HbN. It’s a slurry mix that’s the consistency of whole milk. I dip a patch on a cleaning rod in the slurry and coat the bore twice. Leave the alcohol to evaporate (30mins) before shooting. I do this before each shoot. 
After each shoot, I only use a carbon remover.

On average, I shoot between 100 and 200rounds a session. I like to clean the carbon out after each shoot due to the possibility of corrosion. I don’t really worry about copper.

My 1st cold bore shot is essentially on top of each subsequent shot. My most recent shoot was Warminster. With my big .338 Norma Mag (also using HbN coated bullets, bore and same cleaning regime), I put all three bullets into the size of a 20p during my HME test at 200yds, with no prior sighters. For me, I believe coating works well. And I’m hoping the throats of all my barrels will last just a bit longer due to the ceramic coating. Time will tell.