FYI-6.5 Sherman, 156 & Retumbo

[dok7mm]

Rich, I forgot to mention my SS is 24" + brake. I wanted a bit lighter rig so I went with 2B contours and could only find 24 inchers.

Shooting Lance's H1000 dope I wasn't getting near his velocity and I went 1.5 gr higher. Maybe it's the barrel with only 58 rds thru it and 2" less. Time will tell, I guess.

 

[elkaholic]

Rich, I forgot to mention my SS is 24" + brake. I wanted a bit lighter rig so I went with 2B contours and could only find 24 inchers.

Shooting Lance's H1000 dope I wasn't getting near his velocity and I went 1.5 gr higher. Maybe it's the barrel with only 58 rds thru it and 2" less. Time will tell, I guess.

Probably 25'/Inch I'd guess. N565 is working well for me in the sst. I never did get as much out of H1000 as several other powders.

 

[dok7mm]

The only powder I don't have.

 

[elkaholic]

The only powder I don't have.

I think its its still available. Several guys are liking it.

 

[rockwallraider]

Have it at mid south. It is killer in both my 6.5ss and 25sst

 

[rockwallraider]

Super clean too

 

[elkaholic]

Have it at mid south. It is killer in both my 6.5ss and 25sst

and the 6.5 sst and the 7 ss

 

[dok7mm]

I'll get some, but not sure I'll have time to get load finished in time to head to the mountains. ( 2 weeks, just maybe ).

 

[elkaholic]

I'll get some, but not sure I'll have time to get load finished in time to head to the mountains. ( 2 weeks, just maybe ).

A man with your ability: no problem!

 

[lancetkenyon]

I switched to RL23 w. 156s in my 26" 1:7.5" 6.5SS, still only 74 rounds down the barrel, but hit 3078fps into one of the 3 best groups I have ever shot (which I might never do again). Once it cools down in Phoenix, I will be testing some RL26 for winter hunts.

 

[dok7mm]

I switched to RL23 w. 156s in my 26" 1:7.5" 6.5SS, still only 74 rounds down the barrel, but hit 3078fps into one of the 3 best groups I have ever shot (which I might never do again). Once it cools down in Phoenix, I will be testing some RL26 for winter hunts.

Lance, I was 200 fps behind you with 1.5 grs. more than your load with no pressure. 24" barrel and 50 rds fired. Going to add 50 rds to barrel and then try something different. Also maybe just different lot #.

 

[rockwallraider]

I'll get some, but not sure I'll have time to get load finished in time to head to the mountains. ( 2 weeks, just maybe ).

Won't be hard to load for with n565. You will find nodes all over the place

 

[Bro Dave]

I finally got around to trying the 156 Berger in my .235" free bore 6.5 Sherman LA with Retumbo. This is my 2nd barrel (276 rds) on a SwitchLug build by Clayton @ West Texas Ordnance. Stiller Tac 300, Bartlein 3B, 5R 1: 8, 26" in Manners EH-1, and March F1, 3-24x52. Current barrel is about 50 fps faster than first barrel and shoots 140s @ 3175 with no pressure.

Using once fired 280 Norma brass, I expected there would be some variance in velocities, so I loaded 3 rounds of each charge weight to even things out and get my cases fully formed. Cases are annealed each firing. 156s have been sorted by BTO prior to coating with HBN and barrel was treated with HBN slurry. All rounds shot @ 100 yds with no wind hold, as the velocity and ES were my primary objective.

I started with lower charges than needed, just to get a second firing on 50 cases. I shot charge weights from 56.5 gr. (2,728 ) up to 62.5 (3,038 fps) cooling to ambient temperature between shots. I had zero pressure signs at my max load, so I'll see how far up I can go. I deprime on a separate press, so I'll check for loose primer pockets.

I just picked .010" jump for pressure testing for now. CBTO is
2.904" and COAL is 3.596" on my Sherman #2 reamer, .235 FB. Conditions varied thru the day, temperature ranged 81* to 94*, wind was 5-12 mph back and forth from 3:00 to 4:30. Til noon there was cloud cover, afternoon the sun was out w/heavy mirage. It is indicated in the verticle on the last 4 targets.

This was a fast barrel with HBN, so work up safely for your barrel.
Targets are below. Hope this helps if you can use the data. I'll post my
final results when I'm finished.View attachment 151430 View attachment 151430 View attachment 151437 View attachment 151437 View attachment 151429 View attachment 151428
Sorry they are out of order.

I like your targets. who makes them?

 

[Dan LaChance]

I finally got around to trying the 156 Berger in my .235" free bore 6.5 Sherman LA with Retumbo. This is my 2nd barrel (276 rds) on a SwitchLug build by Clayton @ West Texas Ordnance. Stiller Tac 300, Bartlein 3B, 5R 1: 8, 26" in Manners EH-1, and March F1, 3-24x52. Current barrel is about 50 fps faster than first barrel and shoots 140s @ 3175 with no pressure.

Using once fired 280 Norma brass, I expected there would be some variance in velocities, so I loaded 3 rounds of each charge weight to even things out and get my cases fully formed. Cases are annealed each firing. 156s have been sorted by BTO prior to coating with HBN and barrel was treated with HBN slurry. All rounds shot @ 100 yds with no wind hold, as the velocity and ES were my primary objective.

I started with lower charges than needed, just to get a second firing on 50 cases. I shot charge weights from 56.5 gr. (2,728 ) up to 62.5 (3,038 fps) cooling to ambient temperature between shots. I had zero pressure signs at my max load, so I'll see how far up I can go. I deprime on a separate press, so I'll check for loose primer pockets.

I just picked .010" jump for pressure testing for now. CBTO is
2.904" and COAL is 3.596" on my Sherman #2 reamer, .235 FB. Conditions varied thru the day, temperature ranged 81* to 94*, wind was 5-12 mph back and forth from 3:00 to 4:30. Til noon there was cloud cover, afternoon the sun was out w/heavy mirage. It is indicated in the verticle on the last 4 targets.

This was a fast barrel with HBN, so work up safely for your barrel.
Targets are below. Hope this helps if you can use the data. I'll post my
final results when I'm finished.View attachment 151430 View attachment 151430 View attachment 151437 View attachment 151437 View attachment 151429 View attachment 151428
Sorry they are out of order.

Berger twist cal. claims you need 1-7.5 min rate, but your groups look good.