Could be a tight barrel. I'm at 250 rounds on it so it's definitely broke in!
7 mm SHERMAN SHORTMAG vs 7 SAUM
- Thread starter elkaholic
- Start date
Help Support Long Range Hunting Forum
This is a great thread, very informative. I'm sitting here with a Defiance medium action and wondering what to build when I already have a 6.5 SAUM, 6.5 PRC, and 7 SAUM rifles in the stable! A SS sounds fun!
ruby76
Well-Known Member
A Sherman Max would make the most out of your action.
Rardoin
Well-Known Member
In the 7 SS VihtaVuori N165 has been working really well with the heavies- Berger 190 LR Hybrid and the Hornady 190 A-tip.
I've been focusing on the A-tips since I am using this cartridge for long range target shooting (F Class- Open). I am running them with 60.0-60.2gr N165, 0.0015" neck tension, 0.032" off the lands (0.060" off works well too) and Vavg right at 2800fps in a 30" barrel. Just shot a 100shot/600yd match this weekend over 2 days. I had only 3 shots outside of the 6" 10 ring and 65 shots were touching the 3" X ring. A Berger 195gr hunting VLD/N165 would be a great choice in this gun for LR kills and could get over 2900 fps without trashing the primer pockets. Also, the single base VV powders in this burn range are exceptionally kind to the throat area.
I've been focusing on the A-tips since I am using this cartridge for long range target shooting (F Class- Open). I am running them with 60.0-60.2gr N165, 0.0015" neck tension, 0.032" off the lands (0.060" off works well too) and Vavg right at 2800fps in a 30" barrel. Just shot a 100shot/600yd match this weekend over 2 days. I had only 3 shots outside of the 6" 10 ring and 65 shots were touching the 3" X ring. A Berger 195gr hunting VLD/N165 would be a great choice in this gun for LR kills and could get over 2900 fps without trashing the primer pockets. Also, the single base VV powders in this burn range are exceptionally kind to the throat area.
elkaholic
Well-Known Member
Congrats Robin! It sounds like you and the 7SS are a great match in F class.
Thank you for the good data on N165.
Rardoin
Well-Known Member
Yes, Rich. The 7 SS has proven to be ridiculously easy to acquire a very good tune and easier than any cartridge I've shot to get an exceptional tune. I wanted to prove that a high BC 7mm could compete very favorably with the .30 cal short magnums at 600-1000yds without the recoil/percussion penalty that can be fatiguing over long multiday matches. It appears that it can do just that.
Hi all, new to the forum. Was going to build a 7SAUM but convinced to go with 7SS after reading this whole thread.
This will be my first custom rifle, and budget is pretty flexible.
Do any of you have a recommended smith in the northern Utah/Southern Idaho areas for working with on this? Or is there a remage option I haven't found yet?
This will be my first custom rifle, and budget is pretty flexible.
Do any of you have a recommended smith in the northern Utah/Southern Idaho areas for working with on this? Or is there a remage option I haven't found yet?
elkaholic
Well-Known Member
Call Garrett Preece in Ogden. (Preece Precision)
Rardoin
Well-Known Member
I just measured the throat on my 7 SS after not checking for over 1300rds. At 100 rds it was 2.465" and at 1427rds it is 2.483"....total erosion of 0.012". That is the slowest erosion I have seen in any of my rifles. I am shooting a 190 Hornady and Vihtavuori N165 since about 300rds and H1000 prior to that. The cartridge design is about as perfect as can get for heavy 7mm bullets IMO.
Last edited:
elkaholic
Well-Known Member
That is great data Robin. Thx for sharing!
A greater portion of the powder volume burns within the case with the 40 degree shoulder and short burn column. This makes the case more efficient and attains greater velocity in short barrels than normal. Add to that a .331" long neck and the flame point is more contained in the neck rather than in the throat, and eroision is reduced
Here is some added good news.
Fully formed brass is now available 40 degree)
Some load data to add to the registry for the 7SS. I just finished load development w/ the Berger 190gr LRHT and RL23. 60.2gr @ 2813. COAL is 2.960. I'll measure the CBTO later and update. Pic is group shot at 506 yards today. Rifle is built off a short action TL3 w/ a 22" 1:8 carbon Proof running a 4" suppressor. I shot the pressure test on a different day than the ladder, which probably accounts for the ~10fps difference...based on the outcome though I'm not too worried about it.
Attachments
Last edited:
I too was getting ready to build another rifle in 7mm and came across this thread. I was going to build a 7-08 so my boys could use it too, then started considering the 7 saum and found this thread. I just received my 26" Bartlein barrel with 1-9 twist and I have everything except the action ready to go. Do you think the 9 twist is fine or should I go with a different twist for the 7ss?
Rardoin
Well-Known Member
The 9 will be fine for anything shorter than the 184gr Berger. If looking at the high BC 190-195 class bullets go with an 8tw. I use my 7 SS for long range competition with the 190 A-tips which are very long bullets and they perform very well with an 8.25tw at near sea level but I think I am close on stability. The guys I know running 8.5tw barrels with the 190+ bullets aren't getting the results I am seeing and I think the twist rate has a little to do with it.
Last edited:
Rardoin
Well-Known Member
@elkaholic Rich, when I decided to test the 7SS for F-class my goal to have a case that will push heavy for caliber high BC 7mm bullets at competitive velocities and have barrel life better than a 7 SAUM. I was expecting 1400rds of precision/competitive barrel life. I just shot the Texas State Rifle Association 600yd championship this past weekend using the 7 SS/190 Hornady A-tips/N165 running at 2730-40fps. I decided to run my first barrel since I have not had time to finalize load development in the second. I started to weekend with over 1450rds and I was not certain that it would still group tight enough to be in the hunt with the top shooters but figured I would go with it anyway. Much to my chagrin the barrel was still capable of cleaning the F-class target in some pre-frontal system very stiff winds. An even greater surprise was finding myself tied by score for the lead but well behind by 9 X's (tiebreakers). The front came through as we were starting the final day matches and blew 20-25 with recorded gusts near 40mph. I was able to still hold second/tied for first by score but, on the last match, I closed the X count to 3...which told me this barrel, at 1600rds, has lost nothing since new! I am flattened by the extremely low throat erosion that N165 is getting me with the very long bearing surface bullets. I hope more 7SS shooters give N165 a test.
