Sherman 7 MAX
- Thread starter BCX
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He has his own head stamped brass made by ADG. Don't hold your breath on Lapua ever making it.
77 gr case capacity. Berger 195 @ 3K FPS from a 26 inch barrel.
I've looked at it. It's one of those calibers that I can't figure out why I need a barrel for my Origin (I can only shoot to 1,000 yards), and yet I still want one..........
Was really thinking about doing a 7mm LRC, (338 Lapua short improved necked down to 7mm and 84 gr. capacity). There was a 300 LRC, too, but can't find a single post with performance data on either one after Swamplord announced reamers and brass were available last December. He must have let that project die for some reason and apparently nobody else built one. Too bad, should have been a fantastic cartridge.
While the performance may be a little less than the LRC should have been, I at least know the 7 sherman max will be supported by lots of data and regular updates (like all Sherman's other projects) so I'll know what performance to expect before buying in. May go this route.
While the performance may be a little less than the LRC should have been, I at least know the 7 sherman max will be supported by lots of data and regular updates (like all Sherman's other projects) so I'll know what performance to expect before buying in. May go this route.
Just ran 20 quick rounds to start fire forming brass and get a baseline on accuracy. Rifle shot in the mid .2s to low .3s. 195 Berger's loaded at 3.200 w RL-26. Hopefully when i turn up the boost on the Max.. she stays tight.
Looking forward to seeing some updates on this round. Might need to build one...
I loaded a few test rounds, testing in the morning. I did notice how easy the primers seated on once fired brass w a mild fire form charge. ADG brass is nice but the primer pockets are NOT tight like Lapua. I hope she holds tight.
My primers were never super tight but I’m shooting brass tomorrow on it’s 17th firing.
Priming feel was still excellent on them.
I hope your correct. Only reason i mentioned it was another member said a primer almost fell out. You should have flattened primers long before one ejects itself.
First time using N570. Huge kernels. 70 Grains filled the case nicely but leaves a lot of air gap in between kernels. Seated the bullet and no crunch.
Little morning testing w Berger 190 w 70 grains N570. Primers held no problem, no flat primers but a light ejector mark which may go away when my Amp pilot comes available. Will measure case head expansion later and compare to the lower charge weights.
for those bullets.
I still like the idea of a 28 Nosler throated long w 190 A-Tips. Maybe next years project on a Surgeon 1086 and Bartleins new 400MODBB.
I have been developing my 7/300 wsm with the berger 190 and the son of a bitch just likes to be in that 2830-2880 mv range with H1000, RL 25, and RL 26, but only 62-65 gr in 30” bbl....quickload says N570 would be faster and your results prove this, I have no n570....nice looking rifle and results, congrats
I have a long way to go before i settle on a load. Barrel should speed up a bit. Only had 50 down the tube this morning. Both those loads kept all bullets touching at 100. Will get some 1k testing in tomorrow and might take it to Ohio next weekend to play at the mile.
I've been shooting a 7/300 wsm for a few years as my ELR practice gun. I've been using 180s because I bought a big pile of them cheap and they've been effective to the last target on our range at 2300 yards. Its a short action and I load the 180s for that gun at 2.950" to mag feed.
I just finished another rifle in 7/300wsm and throated it to take the 190 Atips at 3.250". I was just going to start with the H4831 I use with the 180s, but after running your N570 load through QL, I think I'll start there. The case capacities are nearly the same, and it looks like the combination of a heavier bullet loaded longer gets the stars to align for N570. So thanks for that info as well.
Yes, I'll start with a pressure ladder that's several grains low and work up.
I just finished another rifle in 7/300wsm and throated it to take the 190 Atips at 3.250". I was just going to start with the H4831 I use with the 180s, but after running your N570 load through QL, I think I'll start there. The case capacities are nearly the same, and it looks like the combination of a heavier bullet loaded longer gets the stars to align for N570. So thanks for that info as well.
Yes, I'll start with a pressure ladder that's several grains low and work up.
With your data, I'll be able to start with a pressure ladder for N570 using large rifle magnum primers rather than doing 1 for both large rifle and large rifle magnum. I get the best results with H4831 using large rifle primers.
With my 300wm, the lowest velocity spreads came from large rifle primers if single base powders (H1000) were used, but they'd completely shit the bed with double based powders (R26, R33, N570).
With a 338 Lapua case capacity, the large rifle magnum primers worked best for both types of powder.
Tested both those loads at 1K this morning. The 68 gr N570 was the winner. Went 10 for 10 pretty much touching on a half moa round target prone from a hunting rifle. Love it....time to load some for Ohio and the 1 mile target. We will see how it holds up to my 338 LM AI w 300 Berger's.
Played w the 190 A-tip and N-570 this morning. No pressure signs! Just shy of the magical 3k mark. 3 charge weights all shot in the .3’s. Testing at 1k this weekend.
190 A-tip N570 still no pressure signs. Going to go a little hotter. I think I can max out at 3050 fps 
... didn’t measure powder w my usual sequence.
... didn’t measure powder w my usual sequence.
7 Max w some new glass. Tangent Theta LRH to lighten it up a bit.
The 190 A-tip is out shooting the Berger 190 now that I worked a load. My .25 moa A-tip load is still holding .25 moa at 300. 190 A-tip at 3k fps!!!!! Excuse the canted crosshairs LOL.
D
Ran the 190 A-Tip w N570 up to 70 gr... which is about max in my rifle. Light ejector marks, no heavy bolt lift. No change in velocity w 69.8-70 gr N 570 yielded 3033 FPS in 26 inch barrel @ 40 degrees. Settled on 69.1 N570 which gives me 3000 FPS w the best accuracy. Smacked a small rock at 881 yards to ck my cold bore shot for POI and the report says it hits w authority.
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