7mm Sherman MAX complete

[hseII]

Yes, the Max. Korhil is correct on the coal. I had previously mentioned 3.090" but that is not what the 195 is. I measured mine at about 1.167" which is likely just bullet length variation. I shot mine again yesterday at 3000' with 69 grs N570 behind the 195. I also tried 565 for the first time. 65 grains made 2902'. I would caution though that your barrel may pressure up faster. These Rock barrels seem to build pressure slower than most Ive shot.
i. e. you may get the same velocity/pressure with as much as 2 grains less charge?

So 3.167"?

I'm sticking with the .300SS as soon as you get the new Reamer in.

 

[hseII]

Yes...it is one of Rich Sherman's wildcats. It's a blown out 7mm SAUM case.

My loaded round measures 2.422" (touching the rifling) with the Hornady gauge or 3.172" measured just with the calipers. That's with a 195 Gr Berger.

The case itself measures 2.010"-2.013" when fire-formed where the regular 7mm SAUM case is around 2.023". The body of the fire-formed case is .547" where the regular case measures around .540".

I thought that's what the SS was but evidently there is another line.

Looks like I'm onboard the .300 SS.

 

[elkaholic]

So 3.167"?

I'm sticking with the .300SS as soon as you get the new Reamer in.

yes, 3.170" ish with a 195

 

[Korhil78]

I thought that's what the SS was but evidently there is another line.

Looks like I'm onboard the .300 SS.

Can't go wrong with it either.

 

[Korhil78]

50 rounds

A little update. Just went out this morning and fireformed 50 rounds to start load development. Used 58 Gr of H1000 and some 195 Gr Berger's seat right to the rifling to see what it would do. Pretty impressive for a low charge fireforming load. I have 60 rounds down the tube now after I fired and cleaned for the first ten rounds. It cleaned right up after that!

 

[elkaholic]

Lookin' good!!

 

[highdrum]

Man this cartridge looks pretty sweet. Runs with the larger cases very well. Performance like it has another 5-10gr capacity. I have a 26" proof sendero 1:8 laying in the safe. I might have to start looking for a cheap Tikka donor to build one these off of.

 

[Korhil78]

Got 50 pieces of brass fireformed last weekend. I will be doing a seating depth test to start out. I have those rounds loaded up and will be shooting them this Saturday. I will post the results on here. I will only be doing this at 100 yards but after that, I will be doing a powder charge test at 400 yards. I am doing the seating depth test with 60 gr of RL-26 and the 195 gr Berger. A mild load but I will work up when I do the powder charge test.

 

[Korhil78]

Well got out today with not too much time so I did a seating depth test from .010"-.035" in .005" increments with my starting powder charge of 60gr of RL26. Below are the results. Only 3 shots per at 100 yards but it gives me a small idea and gets some more rounds down the tube to level out the velocity.
Pretty impressed that the ES between all the loads with different seating depths was just 15 FPS.

 

[elkaholic]

nice and consistent

 

[Korhil78]

Well I had to put a halt on the 195 Gr load work up. Took my 10 year old kid out to shoot a round to see how it felt to him and it was a little too much recoil for him even with the brake on. He is a small kid so I can understand that.

Got some 7mm 155 Gr Federal Edge TLR bullets to try. Gonna do a seating depth test tomorrow. Will post the results.

 

[elkaholic]

Well I had to put a halt on the 195 Gr load work up. Took my 10 year old kid out to shoot a round to see how it felt to him and it was a little too much recoil for him even with the brake on. He is a small kid so I can understand that.

Got some 7mm 155 Gr Federal Edge TLR bullets to try. Gonna do a seating depth test tomorrow. Will post the results.

The 175 EH is noticably better and they shoot well. I have some 155's but haven't tried them yet. The 190s in 30 sm didnt shoot that well and it likes everything.

 

[Korhil78]

I'm going to try RL17. It should work well.

 

[elkaholic]

I'm going to try RL17. It should work well.

probably will. H100V and N550 also