7-378

GCarlton53 · #1 02-10-2011, 04:02 PM

i know you all have discussed this probly 1000 times but i couldnt find it. i was thinking of a 7-378. i want as close to 4000fps as i can get. i know it will burn barrels but after getting a load worked up it wont be shot but several times a year. can i do it with this round? has anyone shot it? how tight of a group am i looking at with it? can it be fast and still stack'em tight? i know kirby allen makes a 7am that is great. i know he pushes the lapua brass to higher pressures than the weatherby but doesent that cause more erosion? i just have some doubts and need some advice. If i cant get 1/2 to 3/4 of an inch at 100 there isnt much of a point.

thanks very much for suggestions

RH300UM · #2 02-10-2011, 06:11 PM

Good luck finding a bullet that can deliver what you expect!!!

Try talking to KIRBY ALLEN,aka FIFTY DRIVER on this forum. The man is a wealth of info and always willing to share if asked.

GCarlton53 · #3 02-10-2011, 07:55 PM

yeah i tried him the other day. i know he is swamped so i havent tried again. I like the way his 7am looks. i was wondering what kind of group you can get out of these super mags?

davewilson · #4 02-10-2011, 08:18 PM

one of the problems with the 7-378 is you have to use wet coal to get a slow enough burn rate...that's just a wee bit on the overbore side. how bout a 7-cheytac?

GCarlton53 · #5 02-10-2011, 09:12 PM

wouldnt that be worse? i thought the cheytac was more on the 50 cal , 416 barrett level. kirby has the 7am , lapua case. i want the fastest i can get with good accuracy, so if i got to slow it down i will.

Long Time Long Ranger · #6 02-10-2011, 10:32 PM

Gcarlton, It is to overbore and not as effective as you might think. When a cartridge gets to overbore it just loses efficiency. Kirby's 7mm is about as big as you can go. The problem is bullets are not designed for the velocities you can achieve. We did one when I lived in Colorado and I can look up the numbers for you. It was very accurate but we had to use solid bullets like Barnes in it or slow the twist down to where long vld bullets would not stabilize. With faster twists it just blew up bullets. We did get some 175 Sierra game kings to shoot in it at around 3450 fps. The imp lapua case I think is about the max in 7mm. From my experience with this one I would not do another.

AZShooter · #7 02-11-2011, 05:52 AM

I'd like to hear more. Not that I'd want one but it is always fun to see others do wild stuff.

As for bullets that have a fairly high BC and could take the punishment, I found this company by doing a net search. It is called cutting edge. They offer a 170 gr CNC machined copper solid hunting bullet with a BC of .610-630

Cutting Edge Bullets