280 SHERMAN MAX vs .280 A.I.

elkaholic

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There have been a few questions on a couple of other threads concerning case capacities of these cartridges so I did a very accurate test today. I took a new .280 A.I. Nosler case and put in an old primer and then weighed the case. I then filled it to the brim with H20 and re-weighed and subracted the difference. The capacity in H20 was 73.4 grains. I then fireformed the same case in my .300 Sherman chamber and necked it back down to .280 and repeated the H20 process. The capacity was exactly 76 grains. This gives a 3.6 grain increase over the A.I. for a gain of 4.7%...........Rich
 

sinarms

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Rich, I don't know what a Sherman Max is yet but I think you added wrong or put the wrong numbers down. It should be a 2.6gr difference by your numbers. What is the base cartridge for the Sherman Max?
 

J E Custom

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There have been a few questions on a couple of other threads concerning case capacities of these cartridges so I did a very accurate test today. I took a new .280 A.I. Nosler case and put in an old primer and then weighed the case. I then filled it to the brim with H20 and re-weighed and subracted the difference. The capacity in H20 was 73.4 grains. I then fireformed the same case in my .300 Sherman chamber and necked it back down to .280 and repeated the H20 process. The capacity was exactly 76 grains. This gives a 3.6 grain increase over the A.I. for a gain of 4.7%...........Rich

Hello Rich.
I can't find the reamer dimensions on the Sherman so the question is , Can you fire form a 280 rem
to the Sherman? Just like the 280 AI.

J E CUSTOM
 

elkaholic

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Hello Rich.
I can't find the reamer dimensions on the Sherman so the question is , Can you fire form a 280 rem
to the Sherman? Just like the 280 AI.

J E CUSTOM

Hi Jerry. Good to hear from you. You can but not as simple as chambering the .280 and firing as in the A.I. If I were going to use the std. .280 case, I would first neck up to .308 and then back down to .284 leaving a false shoulder to headspace against. My case measures 2.150" body length to shoulder and my .300 is 2.223 to the neck junction so a .280 would be about 2.237" give or take a couple thou to the neck. Diameter at the body/shoulder junction is .460". You can use my reamer:D....Rich
 

bigngreen

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What kinda numbers do you get with bullets like the 168 or 180 Berger, my dad is putting together a 6.5 Sherman soon and I'm really looking forward to seeing what it will do, if it performs like it looks the speed goats better stay waaaayyy out of range gun)
 

elkaholic

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Hi Bign'.......I had no idea he was your dad! Ya, that 6.5 will definitely outrun a speedgoat:D I don't have a .280 put together yet but a guy in Lewistown is building one this summer so should have some real data before too long. My guess is that 3150' should be possible with a 168 in a 26" tube. The 6.5 will exceed 3200' with a 26' and I get 3100 with 190 SXR's out of my 300 Sherman with a 28". You'd better build a .280 to stay ahead of your dad:D........Rich
 

elkaholic

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Old thread but my the .280 Sherman has my interest. Has anyone got any actual data from the 168s or 180s?

The guy from Lewistown had a lot of trouble with his gunsmith and we are going to rebuild it. We did a little work with it before he had it tied up for over a year and the velocities were impressive. It will exceed 3100' with the 168's. We didn't get to try anything heavier before it went back.
You can count on it outperforming an A.I. for sure!.......Rich
 

elkaholic

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Have you compared the sherman to the gibbs version?

I haven't, but the 6.5 Sherman and Gibbs are identical in velocity and case capacity so the 280 should be as well. Where the Sherman has it over the Gibbs is a far better case design. The Sherman has less body taper, a 40 degree shoulder, and a MUCH longer neck which is the best part.......rich
 

Jcub

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I haven't, but the 6.5 Sherman and Gibbs are identical in velocity and case capacity so the 280 should be as well. Where the Sherman has it over the Gibbs is a far better case design. The Sherman has less body taper, a 40 degree shoulder, and a MUCH longer neck which is the best part.......rich

I have a SAAMI .280 AI, could you post a picture of 1 next to your Sherman Max?
 

elkaholic

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I have a SAAMI .280 AI, could you post a picture of 1 next to your Sherman Max?

I don't know if I have any A.I. brass but will post if I can find one. It looks very similar to the A.I. but has less body taper and the body is longer.....Rich
 

bigngreen

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I think my dad has some 280 AI factory brass that he was going to form some Sherman cases from, I could see if he could put them beside a 6.5 Sherman case and get a picture.
 

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