I reached out to both tikka and proof to see if their action can handle the excessive pressures associated with 7 BC. Haven’t heard back yet. But I figure since proof is offering 7 BC prefits for tikka they either have a guarantee from tikka or have done their own in house testing. The only info I could find says tikka test their actions 120-130% over pressure. Their highest pressure cartridge I believe is 65000 psi which means theoretically they test up to 85000 psi which seems to be cutting it close to 80000 psi of the 7 bc. Having handled their actions, they seem hard and dense compared to other actions so I can’t imagine they wouldn’t be able to handle the excess pressures but it just seems too cowboy to assume they can tolerate it without any assurances. Anyone slap a proof 7 bc barrel on a tikka yet?
Following with interest.
The 7BC proponents say that it doesn’t matter, any modern action will handle it because the metal case actually handles the pressure.
The 7BC opponents say that’s absolute garbage. The whole reason why Seekins developed a brand new action for “3” series was to handle the higher pressure of the BC as well as the 277, as well as whatever else comes down the road
Interesting times
Cool.
Going to give it a try??
lol, yeah, I think I will at some point. I just built a 338 NM that I’ve been enjoying so I’ll probably wait a bit before lighting the ‘ol Benjamin’s on fire again. How about you? The other hesitation is the reloading situation. I wouldn’t mind having a hunting rig that only shoots factory ammo but half the fun is in reloading.
Still on the fence myself. The reloading thing is the main hang up.
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I’d really like to use different bullets than what’s currently available ( that can obviously change if Federal starts putting out even more variety or some other company can start loading for it which I don’t think can even happen)
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I really prefer to download it a little bit. Not really looking for 7 PRC/RM performance out of a 16-in barrel, but would be tickled pink if I could get 280 Ackley performance out of a 16 inch
Yeah, I really like 7 SAUM. I built both a heavy longe range rifle and a lighter weight, shorter barrel hunting setup and boy are they fun to shoot. The shorty barrel is 20” and it sends the 175 eld-x at 2770 fps. That keeps it above 2000 fps and 1500 ft-lb of energy out past 600 yards. Now I just have to convince AZGFD to pick me for an elk tag, lol. Never expected it would be a multi year wait, lol.
What’s your long range 7SAUM?
I’ve got a 22in Fierce 7SAUM now, and have been considering switching a 6.5 PRC to a second 7SAUM.
Cool!
Ever hunt with it?
Do you use the same hand load for it and the shorter gun?
I mainly shoot 180 eld-ms out of it. I also have some 183 smk hpbts that I need to develop too. I’ve put the 175 eld x loads for the shorter hunting rifle through the big boy but I haven’t put the 180 Eld ms through hunting rifle.
I haven’t hunted with the 7 saums yet. Hopefully this fall.
Good deal
I’ll have to look when I get home at my notes tonight, but 2770 out of a 20-in barrel with a 175 is quite impressive. That’s about the speed I believe I get out of my 162’s with a 22 inch barrel.
7SAUM and 280AI are pretty darn optimal calibers for hunting here in the US
It was about 95 degrees when I got those velocities down here in AZ, so assuming it’ll be cooler for a fall/winter time hunt, I’ll probably lose some velocity. That was the top of my ladder and there was some slight flattening of the primer but no heavy bolt lift, ejector mark or anything else to suggest over pressure. My SDs were a little better at around 58.5 to 59.0 gr so I might back off a bit, which would put me at the mid 2600s which is still pretty good for a 20” barrel slinging 175 grains.
The load that got me 2770 is 175 eld-x
N560 61.0 gr
CCI 200 large rifle primers
ADG brass
I’ve got a 280AI load with a Hammer and N560. Developed it in the summer. Never got a chance to test it or hunt with it in the winter to see if it would change much.
My SAUM uses H4350. For the first time ever with this I tried the Hornady method for load development.[ load one grain off of Max, pick a coal which works for your gun, shoot 10 shots. If it sucks you’re done with that powder. If it looks good then verify with 20 more]
It went well with this occasion. I also however wasn’t looking for a F-class capable load. I would have been happy with anything MOA or better and ended up with about 0.7-0.8.
I might be able to get it faster with some more tinkering, or even tighter. However, I’m quite happy with what it is right now. It’s rare that we shoot over a hundred yards around here, the longest I’ve ever seen is 300.
I asked an executive at Sako/Tikka about the action and he said they haven’t fully developed everything for high pressure but he thinks it’ll work.
Good to hear! This inspires confidence that I won’t blow up an action in my face. That 20” proof 7 BC tikka prefit is looking mighty tempting.
I’ll have to give that hornady method a try. Makes sense. I’ve been happy with the vitahvuori powders. I’ve been using n570 for the 338 NM. That stuff is powerful. The load data is super wonky for that cartridge. I thought there’d be more support for it. Sierra’s data is super conservative, and there’s not really much else out there. I did some initial testing and it seems to tolerate a lot more powder than their max load. And Norma uses their own powders I guess. But max loads from Sierra for the 300 hpbt are supposed to be 2500. But Norma has them up into low 2700s with their powder. So much fun to shoot though. Cant wait to take it out again later this week.
I’ve used it twice, with that SAUM and a 300WSM, and it worked well for both. Not sure what I’m going to do with my next project comes up. I’m eagerly watching the current little crow Gun Works series on load development.
Speaking of the WSM, kind of similar to what you noticed with the 338NM, If you look at VVs load data site, with the Barnes Bullets it’s quoting velocities that are maxing out at least 200 ft per second slower than what Barnes quotes on their website. Exact same thing if you look at their data on Hornady bullets and compare it to what Hornady reports.
I bet they ran that by their lawyer before responding