Sherman SWC 7mm

I can't find any webpages on the topic, and I don't have the magazine.

I'm just imagining what could be possible, but nothing great is coming to mind. The parent case, the 6.5x47L, is already undersized for the 6.5mm caliber in that it can only push the heaviest, highest-BC bullets to about 2600fps in a 26" barrel. I say this as a person that built one this year and is doing exactly this. To neck it up to a 7mm, one would be running the heaviest bullets at something like 2400fps, which is going to impress no one.

The most impressive performance with a 47L case, I think, comes from a 25-6.5x47L Ackley Improved.
 
adamg said:
I can't find any webpages on the topic, and I don't have the magazine.

I'm just imagining what could be possible, but nothing great is coming to mind. The parent case, the 6.5x47L, is already undersized for the 6.5mm caliber in that it can only push the heaviest, highest-BC bullets to about 2600fps in a 26" barrel. I say this as a person that built one this year and is doing exactly this. To neck it up to a 7mm, one would be running the heaviest bullets at something like 2400fps, which is going to impress no one.

The most impressive performance with a 47L case, I think, comes from a 25-6.5x47L Ackley Improved.
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According to what I read, they are running 2700 or so with the 180 and 190 gr bullets. I'm not sure what Sherman does to the case to enlarge capacity, but it must be a substantial increase. And, going by what I know of other Sherman wildcats, likely much higher pressures. Seems like an interesting combo for 1k shooting though. - dan
 
dan belisle said:
According to what I read, they are running 2700 or so with the 180 and 190 gr bullets. I'm not sure what Sherman does to the case to enlarge capacity, but it must be a substantial increase. And, going by what I know of other Sherman wildcats, likely much higher pressures. Seems like an interesting combo for 1k shooting though. - dan
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The F-Class Open guys solved the issue of delivering the most accurate hits on 1000 yard targets years ago. They are slightly tweaking their answer, but generally it appears to be a 7-6.5PRC, 284 Winchester, or some of the .30cal magnums.
 
adamg said:
The F-Class Open guys solved the issue of delivering the most accurate hits on 1000 yard targets years ago. They are slightly tweaking their answer, but generally it appears to be a 7-6.5PRC, 284 Winchester, or some of the .30cal magnums.
Click to expand...

I have a 6.5-284, a 284, and numerous 300 Magnums. This just seemed a more economical and easier option. I think I'll have to give Sherman a call and get some more details. - dan
 
dan belisle said:
I have a 6.5-284, a 284, and numerous 300 Magnums. This just seemed a more economical and easier option. I think I'll have to give Sherman a call and get some more details. - dan
Click to expand...

Ask them what the case capacity is if you don’t mind. Cortina’s “747” could only fire 190’s in the 2500’s.
 
Can't see it being too bad really, barrel life would be good, 6.5CM isn't a screamer with heavy for cal bullets either and handles 1000m decent.
I kind of like it.
My buddy likes shooting long, runs 300Win and 300PRC, but with the nightmare lack of mag primers he built a 6.5x47 and runs small primer brass.
Despite the whimpy recoil, tiny bit of powder, and lack of whack compared to the 300's, he's shot some of the best groups he's ever shot with that thing.
 
I can tell you from first hand experience that 34.8 gr Varget in the 6.5x47L cartridge with the 153.5gr bullet is getting about as spicy as I care to run these days. I can't imagine slamming 41.5 gr into the same case with a drastically heavier bullet.
 
Here's what is on the fb site.

"7mm SWC
Aka “The Donky Dasher”
Testing is going great on the new short action 470BF
Cartridge ��

About 6 months ago I started talking with Rich Sherman about developing the longest case to feed 190class 7mm bullets and not be past neck shoulder junction. Also the goal was to run that bullet 2700 FPS.

The plan was to sherminize a 6.5x47 case and it worked out really well. I chambered up a donated fireforming barrel from a fellow Fclass shooter and we started cranking out brass. Tyler Jacobs and I shot 2 rifles chambered in what we plan on calling the 7SWC in the best in Texas match with very little prep. Both of us used this match to figure out data and recoil management, typically a non issue with the 6 dasher. The following weekend I went to MKM in PA and only lost the match by 2 shots…. This was with 180 hybrids at 2720 and very little load work up. The large advantages I see other than ballistics are the ability to read hits and and misses so much easier. “Rocks the plate!”

I personally wanted a cartridge to dominate ballistically in the PRS world. I think we have succeeded in this task. Here are some numbers that we have seen.
28in strait 8twist
180 Hybrids 340 G7
43gn varget 2825 @pressure
41gn varget 2720 great results

190 Atips 418G7
41.5gn varget 2750 @pressure
40gn varget 2630 happy

The picture below is a group at 905 yards BC trued out at 418G7 ��
Comparing these numbers to the “6dasher” with 109s
The 7SWC drifts 5.9 inches less in a 4MPH gust. 8-12
& Has about 12inches less wind hold at 900 yards"

There are a couple of pics, which I can't share as I'm at my pic limit. Lots of comments. As for pressure, every Sherman wildcat I have seen runs high pressure. Doesn't seem to deter people much. I'd like to see actual pressure data though. - dan
 
It defeats the purpose of going 7mm if you just run a .340 G7 BC bullet. That's a horrible BC. The 6.5 153.5gr hybrid at .357 G7 BC will strongly outperform the listed 7mm bullet by nature of being faster, higher sectional density and higher BC.

The 190 atip, on the other hand, that's a serious lazer.

In the context of PRS, I'll mention that the 180gr @ 2720fps versus my PRS rifle's 109gr @ 2730fps is 65% more recoil. So it's not free ballistics - you are paying in recoil (and powder).
 
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