Partition vs Accubond Range Test Today

[Ridge_Runner]

mike, its called a 7mm Allen Mag, a 338 lapua mag necked to .284 and improved. the charge is 110 gr of WC872, lapua case, fed 215's, the bullets are jammed about .005. this is from a 30" lilja 9 twist.

I also run the 160's at 3340 fps from my 7mm STW with a 26" lilja 1/9.
RR

 

[DrMike]

Cool. I am not familiar with the cartridge, though I have done some work recently with the 228 Lapua. The velocities with the STW are stepping out there as well. It is certainly more than I have obtained.

 

[Ridge_Runner]

I have no explanation for it, but both my 9 twist 4 groove liljas just seem to be fast. my 140 load in the STW clocks 3550 fps, 2 more grains of H-1000 yields 3602 with no pressure signs except when temps go above 70 degrees, then bolt lift is slightly heavy so I backed it down 2 grains.
The 7mm AM load is a heavy load also if its warm, I was instructed to load it up until the WC872 shot clean and the pocket got loose after the 3rd full power firing, that load clocked right at 3700 with the 160, but the WC872 is very temp sensative, shoot that load (115 gr WC872) at 70 degrees and you have a hard time lifting the bolt, so I backed it down till it was just a tiny bit sooty when fired (just under 60,000 psi) and called it good, my cases are on they're 5th firing and pockets are still tight.

Oh the 7mm Allen Mag, was developed by Kirby Allen of Fort Shaw Montana, he is a world class smith (IMO) and runs a co. called APS (Allen Precision Shooting) its a 338 Lapua with (I think) body taper reduced to 12%, the shoulder moved slightly foreward and a 35 degree shoulder and a case capacity of 122 gr of H2o.
Kirby built the rifle 3 years ago and though I own rifles by Jim Clark, Tim Wilson, Mark Bansner, Ray Romain, and some other unknown guys, I have never held a more accurate or less temperamental rifle in my hands that I know of. It is just incredible.
the first bullet I started working with is the one I shoot today, the 160 AccuBond, when the rifle was ordered I ordered 16 pounds of WC872, its the only powder I've ever shot in it. hows it shoot?
100 yd. .2"
300 yd. .8"
650 yd. 1.8"
850 yd 4-5"
this is shooting off a bipod with rear support.
RR

 

[DrMike]

I have seen similar velocities in Lazzeroni Firebirds with 160 AccuBonds, and I've seen velocities that would match that from Lazzeroni Warbirds shooting 180 grain TSXs and Partitions. I've done a lot of work with Lazzeronnis during the past several years. There is no question but that I see some incredible velocities with these calibres; but I've recently begun backing off the charges because the primer pockets do get loose pretty quickly. Also, despite warning people that the loads are hot, many have a foolish habit of loading up and trying to tweak them to get a little more velocity. Warmer weather is also a problem on such hot loads. Consequently, I have recently informed people that I will not provide load data that will give sticky bolt lift, because too many try to shoot them like they were a 30-06 or a 280. Some of these are custom or semi-custom rifles (usually Pac-nor, Kreiger or Bevin King barrels), and they do seem to shoot quite well and faster than I would otherwise expect. I have no doubt that the Lapua necked down to .284 will produce some great velocities. With the volume of the case, I don't doubt that you see some fast-stepping bullets.

 

[Ridge_Runner]

If you do much shooting with the big jugs, try the 872, its temp sensative but its got to be better for throat life, the reason I worked up the 160 AccuBond load in my STW was to test a theory.
3 shots with 86 gr of H-1000 and a 140 BT clocking 3550 yielded a barrel almost to hot to touch.
3 shots with the 160's and 94 gr of WC872 yielded 3340 fps and a warm barrel, it has to be easier on the throat.
RR

 

[DrMike]

Well, I'll have to see if I can find some. MilSurp powders are somewhat more difficult to obtain in Canada, but I'll see what can be done. The data I dug up looks interesting.