7 mm SHERMAN SHORTMAG vs 7 SAUM

[elkaholic]

Rich,
Why would you grouse about those groups? The one shot a bit off wouldn't really register on an animal would be my thinking. Unless those groups are at 25 yards...

Your mirage and my mirage are pretty much the same. Idaho blow sand gets excessively hot as compared to the air which is the cause of mirage. Air temp can be 80 degrees and the sand will bring blisters to your hand.

My favorite drop test range is a spot where the surface of the earth in no closer than 5' below line of sight and then only for about 5'. Considering trajectory the bullet is no closer than 1000 feet from the bottom of the canyon.

However the wind there continues to kick my butt....

I'm keep'n an eye on ya. Things are looking good.

Hi Roy.....Actually, my 25 yard groups were a bit wider than that! From what I have seen so far, I just know that the rifle is capable of more. I am going to wait for a cloudy day (if that occurs here) and see what I can do with some load developement. I am pretty excited about the velocity/accuracy combo of the 180 so far though......Rich

 

[royinidaho]

A local fella got his 7mm Rem up and running. Zero'd @ 200 and darn good group. He is pushing the 180 Berger as much as he cares to.

Savage action, 27 1/2" pac nor w/poly rifling.

180 Berger @ 2940 w/ 0.350" free bore pushed by 70 gr Retumbo.

Still keep'n an eye on ya.

 

[elkaholic]

A local fella got his 7mm Rem up and running. Zero'd @ 200 and darn good group. He is pushing the 180 Berger as much as he cares to.

Savage action, 27 1/2" pac nor w/poly rifling.

180 Berger @ 2940 w/ 0.350" free bore pushed by 70 gr Retumbo.

Still keep'n an eye on ya.

He needs to stoke that big case up a little!

 

[royinidaho]

I'll let him know.

 

[elkaholic]

Finally got a cool, cloudy day to shoot so I could tell what the real potential is. I loaded up several rounds of RL26 with the 180 Berger hybrids from 58 to 62 grains and seated everything at 2.925". I fired 4 rounds thru a sparkling clean barrel to get everything settled down first and then fired 3 shot groups. The lowest charge grouped just OK. The 59 and 60 gr. charges grouped right at .3". The 61 gr. charge opened up more like the 58 grainer, and the top charge of 62 grs. seemed to settle back in . The 62 grain charge was getting near max, but I felt I could have fired another grain without major case problems. That would put this little fire breather at a tad over 3100'! I may try that later. 62 grains clocked in at 3070' and grouped in 5/8", but I called the last shot as a pull Right! The first 2 shots cut one overlapping hole. I want to test this one again and see if there is another accuracy node this high? The next trip out, I will try playing with the seating depth which should tighten things up a little more. Here are a few pics of the groups......Rich

 

[royinidaho]

Rich,

One of these days we'll have to get together.

Scouting season is upon us so it may be a day or two.

Your cartridge and rig should be giving you great confidence.

I figure with those velocities and any consistent group size under a 1/2 MOA at 100 or beyond a bit is more than sufficient for game taking. Don'tcha think?

 

[elkaholic]

Rich,

One of these days we'll have to get together.

Scouting season is upon us so it may be a day or two.

Your cartridge and rig should be giving you great confidence.

I figure with those velocities and any consistent group size under a 1/2 MOA at 100 or beyond a bit is more than sufficient for game taking. Don'tcha think?

I think it is showing some very good promise Roy! Rhian did a bang up job on the build and it is really fun to shoot. I think with a little tweaking, I may get down in the 2's. For a lightish rifle with a #4 barrel, I am quite pleased. It would be fun to get together some time......Rich

 

[Longtooth32]

Hi Roy (Mr. 270)
There is also a 270 SS being built very soon by a guy who just built a long action 270 Sherman. "Just in case a 270 suits your fancy better"
He reached 3200 with the 165 matrix in a long throated version!! ...........Rich

Do it!…

I have a 270 Weatherby with a 28" Benchmark barrel 1-9 w/ muzzle brake…

I am doing over 3160fps with 74gr of H1000…with the Matrix 165...

The Matrix 165 is doing 3267fps with 75.5 of H1000…

More H1000 gets me over 3300fps with a heavy bolt lift…too hot…

Looking forward to your results...

 

[elkaholic]

I have not had a chance to do any more load developement lately, but was asked to post a pic of the 7SS with a 180 Berger Hybrid loaded. Here is a pic loaded to 2.925" next to a 300 SAUM case for comparison.....Rich

 

[elkaholic]

I went north to set up elk camp this week and finally had a chance to shoot the 7ss at more than 100 yards. The load was a 180 Berger Hyb. at 2960', with 60 grs. RL 26, which is a couple of grains below max. COAL was 2.925". The first shot hit about 8" high at 880 yards so I clicked down and fired again. This shot was perfect height and about 4" left of bull (marked with X) I then dialed in 1/2 moa windage and fired 2 more rounds. Those 2 shots are in the bull and marked with the quarter. Had I fired all three without the windage correction, I would have had 3 shots in 1.5 inches instead of two. This rifle which was built by Rhian (bigngreen), with only a 4 contour barrel, is making me smile.......Rich

 

[muleystalker]

Dam thats nice

 

[elkaholic]

Dam thats nice

Ya, I am really pleased with it! Especially with only a #4 contour......Rich

 

[gillettehunter]

Any idea how the temp sensitivity is on the RL 26? Great velocity with that little case of your. Was working w/ my 7 SAUM and some 180's. I can get to about 2900 FPS with N-570. That has a bit of pressure at that point. Nice shooting. Bruce

 

[elkaholic]

Any idea how the temp sensitivity is on the RL 26? Great velocity with that little case of your. Was working w/ my 7 SAUM and some 180's. I can get to about 2900 FPS with N-570. That has a bit of pressure at that point. Nice shooting. Bruce

Thanks Bruce! Temp sensitivity is the only unknown at this point. It gives very high velocities, and VERY low es even with high pressure loads. I had single digit es with a load that reached 3054 with the 180's.....Rich