Keyhole 7.62x54r BL-C(2)

[4895]

I just got back from the range and much to my surprise, a target full of keyholes sat in front of my eyes.
I loaded up some ammo, a start load of 52.0 grains and a midrange load of 54.0 grains of BL-C(2) for my Russian Mosin Nagant.
Using Hornady 150 grain SPBT bullets, I expected velocity around 2800-2900 fps. Instead, I found a target full of keyholes, some hard extraction, and what seemed to be a couple of "hang-fires" or strange noises like a delayed primer ignition or powder ignition. I have always had good luck with 168 grain .308 bullets and wanted a lighter load for smaller game. I used standard Remington Large Rifle primers. Should I use a magnum primer because of the large case of ball powder? Should I stick with a tried and true powder H4895 or Varget (Had success in past attempts)? I thought BL-C(2) would work well with 7.62x54r as it is good in 7.62x51 Nato? I have slugged the bore and it was .312" lands, .314" grooves, IIRC. Any help is appreciated. Thank you.

 

[NCsmitty]

Well first off, BLC2 should be used with a magnum primer for proper ignition in a larger case like the 7.62x54R.
I don't know how that you have had good luck with .308" bullets in a 314" bore, and if you have .312" lands, then the rifling is worn out.
IMO, the undersize bullets are the reason for your keyholing, and you need to get some bullets that are closer to groove diameter. Your powder choice is a good one, and if you use magnum primers, you wont have hang-fires.



NCsmitty

 

[FROGO207]

Agreed, the bullets need to be larger for them to engage the rifling . My Mosin needs .312 bullets to be anywhere accurate and my bore slugged .310. So .308 bullets are a waste of time loading if used in my rifle.

 

[DaveInFloweryBranchGA]

Like the other two gentlemen have stated, your bullet and your primer is your problem. Get some bullets designed for .303 British and that may help. And change to magnum primers. Slugging your bore will help you match a bullet to it.

 

[4895]

I have had great luck with 150 grain Sierra Match King bullets in .308", producing MOA groups off a sandbag rest. I have a feeling the root cause is the standard primer instead of a magnum large rifle primer. I will slug the barrel again. I should be able to do that today or tomorrow. I did not write the dimensions down and am relying on memory from 6 years ago? Thank you.