6.5x55 Swede load workup

[Jimro]

So I'm in the process of getting together a "Vintage Sniper Rifle" for NRA sanctioned Vintage Sniper Rifle Matches. The rifle will be an M41 reproduction, just a stock M96 Swede with 29" barrel, turned down bolt, short slide side rail, and "authorized substitution" Weaver K4 scope.

Now I have 100 Winchester cases on the way, I use Win brass in my 308 accuracy load and have been happy enough with it that I won't upgrade to Lapua unless there are is no other option.

I also picked up 250 rounds of Nosler Custom Competition 140 gr HPBT bullets.

The powders I have available are: IMR 4064, WC872, and 2000-MR.
Primers available: Wolf/Tula Magnum Rifle, CCI-BR2, CCI 200 Large Rifle, Winchester Large Rifle, Federal GMM Large Rifle.

Data for IMR 4064 is plentiful, but I would like to use that powder mainly for 308 and in 30-06 for my Garand.

Data for 2000-MR is listed for "commercial action", but the velocities listed for a 140 grain bullet seem to be in line with milspec ammunition (however I'm pretty sure they are using a shorter barrel than that on an M96). Also, I would like to use the 2000-MR for 223 match loads.

That leaves the WC872, which I can find some data for from those who have used it for both cast bullets and jacketed bullet. This powder is very slow, and based on some QL calculations someone posted a while back, would take 116% case fill to get to 60K PSI which is about 10K PSI above my comfort level with a small ring Mauser action. I am comfortable using this powder to do an OCW workup to see if I can get to MOA or better.

If at all possible I would like to combine the Wolf LR Magnum Primers, WC872, Win Brass, and Nosler bullet into a combination that can achieve 2,500 fps from the muzzle. This give a standard "2,3,4,4,5" MOA drop from a 100 yard zero out to 600 yards (the longest shot in a Vintage Sniper Rifle Match). If I can get 2,400 fps out of this combination I should be just fine, although my come ups would be "3,4,4,5,5" instead.

So, to sum up, I'm not really looking for max velocity, just looking to see if using WC872 is feasible to safely build up to 100% case fill and stay under 50K max PSI.

Thanks for your time.
Jimro

[SHR970]

Short answer:

I have looked in my Accurate Updated 5th guide circa 1992. They have a listing for their AA8700 powder (WC872 is supposed to use AA8700 data according to GIbBrass). They have a listing for 140 gr. bullets and their spec gun was a 96 Mauser. if you want the data range PM me as this is older data and the use thereof is at your own risk.

Your Win. brass has a ~.473" head (standard for most cartridges); the Swede spec. is .480" You will most likely suffer case head seperations after 3 or 4 firings so watch for it closely. Lapua, Norma, and Privi brass use the right head diameter; data I have is for Norma Brass. .007" doesn't sound like much but it makes a big difference.

[ojibweindian]

Jimro

I second SHR's caution about paying attention to your brass. I'd like to also say that neck-sizing only will most likely extend the life of your brass; I've got 100 piece of Remington brass (necked) on their 5th go-around. I will say, though, that they're gonna get pitched afterwards. I'll be using Lapua from here on out.

If you can swing it, get your hands on Lapua brass for the Swede. As SHR stated, Lapua makes 6.5x55 brass to original specs, and should last a bit longer than any of the U.S. made brass.

Another thing, if you can, get some RL-19 or RL-22. I'm getting an average of 0.995" groups at 100 yards using RL-19, Hornady 140 grain Interlock, and WLR. The Remington cases are neck-sized only.

[Jimro]

I may "bump size" the Winchester brass using my full length sizing die to set the shoulder back around a thousandths, the cock on closing feature makes me leery of buying a neck sizing only die.

Jimro