Best 7mm cartridge?

7Wby is nearly extinct, can't find ammo anywhere, only special order around here. To increase Twist on 7Wby options is to purchase 7RM Rifle and Ream out or AI the 7RM and use 7WBY AMMO. Equals Long Neck with 40 Degree Shoulder and 9 Twist.
Don't have any problem here (Phoenix) with either ammo or brass for 7mm WBY Mag. Brass is $35, ammo is $55 to $92. Hornady 7mm RM ammo is $50. Problem???
 
From what I have found, the 7mmLRM has a case capacity of 99 grains. Seems most guys are running 180s at 3000-3050, again biggest complaint being soft brass. With ADG/Gunwerks brass, I can see this round hitting a node around 3100 like originally designed. Everyone is running H1000 in it as well. Retumbo or RL26 would probably gain you additional 30-50fps on top of H1000. It's a great round and I'd like to mess with one in the future with the new brass coming out for it.
A 7lrm is about 88gr capacity. The parent case(375 ruger) is 99gr capacity. Once the adg made gunwerks brass becomes available, the chamber will be an excellent choice. 180s @ 3100-3150 if feel is possible with RL26 or N565. N570 would work great but eat lands quickly, but maybe not with the extremely long neck.
 
A 7lrm is about 88gr capacity. The parent case(375 ruger) is 99gr capacity. Once the adg made gunwerks brass becomes available, the chamber will be an excellent choice. 180s @ 3100-3150 if feel is possible with RL26 or N565. N570 would work great but eat lands quickly, but maybe not with the extremely long neck.

I agree with highdrum. However, the speeds some are listing are optimistic/overpressure/fast barrel. Here is QuickLOAD run on RL26, N570 goes ~100fps faster as mentioned I could post that too if need be. I haven't used VV N570 yet but have seen many mention the fast land erosion, at least on smaller bores? Anyone have better feedback or links to threads on that? I'm considering just going up to the 300 PRC rather than the 7 and either RL33 or VV570 seem to be the best choices there too.

2020-04-06 (2).png
 
180 gr is the way to go with the 7's. The 195 may work good but it's a really really heavy bullet. The 28 nosler may push it where it would be beneficial but the 180 is just an amazingly good balance of speed and b.c. more than enough for even past 1k.
 
I agree with highdrum. However, the speeds some are listing are optimistic/overpressure/fast barrel. Here is QuickLOAD run on RL26, N570 goes ~100fps faster as mentioned I could post that too if need be. I haven't used VV N570 yet but have seen many mention the fast land erosion, at least on smaller bores? Anyone have better feedback or links to threads on that? I'm considering just going up to the 300 PRC rather than the 7 and either RL33 or VV570 seem to be the best choices there too.

View attachment 185812
I'd run this with a shank seat depth of 350 or so. You're using a lot of powder space with that depth, the bearing surface of the bullet is only 0.430, my rifle was throated for 195s and length with 180s 40k off was 3.56" long. I don't know anyone who'd run a 7mm lrm 220k off lands like your quickload is setup. I know I could run 180s in junk hornady brass at 2975 and have decent brass life with H1000. This was years back before rl26 was available. I think N565 or Retumbo may work well here too.
 
been shooting 7mm for 40 years all kinds of 7mm .7x57 708 7rm 280"s haven't shot
the really big 7's but that you don't need velocity like we did when we didn't have
dial up scopes .my 7rm has about 600 rounds though it and it's about wore out.
it still shoots ok 9/16 or so .with rl 26 and 180gr. berger go's 3008 fps. bigger go's faster
in couple ways. and recoil up too. always looking to improve . but when I'm just busting
steel 7-08 does just find. accuracy winds over velocity all day. most of the shooters at the
range always show me or tell me how great there big guns shoot but when I ask them to show me they always got a problem. there's a reason he little 6br's wind at 1000 yds. and you need the big boy's at a mile or farther. just saying . hope I didn't bore you guys . or go off topic.
I'm stuck in the house.that sucks. stay safe .rich
 
A forum discussion on the best 7mm cartridge would not be complete without including the 7 Allen Mag. Berger 195's at 3350 to 3450 fps.
 
I'd run this with a shank seat depth of 350 or so. You're using a lot of powder space with that depth, the bearing surface of the bullet is only 0.430, my rifle was throated for 195s and length with 180s 40k off was 3.56" long. I don't know anyone who'd run a 7mm lrm 220k off lands like your quickload is setup. I know I could run 180s in junk hornady brass at 2975 and have decent brass life with H1000. This was years back before rl26 was available. I think N565 or Retumbo may work well here too.
Here is a run at that COAL with everything close to max pressure FWIW. In a 7mm, I think the LRM is just about ideal.
2020-04-06 (5).png
 
Last edited:
I dont have personal experience with any of the sherman line. They are undoubtedly a great line of cartridges! But 14 grains difference is ALOT!

The answer to your question is ... Inherited Hornady Hype ..... going to a 40 degree shoulder from 30 degrees DOES NOT increase velocity by 200 fps while magically doubling barrel life, Not sure how grown adult males can believe that nonsense
 
Warning! This thread is more than 4 years ago old.
It's likely that no further discussion is required, in which case we recommend starting a new thread. If however you feel your response is required you can still do so.
Top