375 Sledgehammer

[Seddo]

Hi guys,

I have finally got my 375 Sledgehammer running, Archaos has his SAC barrel in the same calibre so there are now 2 of us with them. I didn't think I would be posting anything until I had the barrel sorted as I still have about a 3 month wait for brass. As I couldn't wait for the dies to arrive I decided to use a brownells expander and open up some 338 kap cases to 375 and start forming. The first 2 rounds were seated with a 338 LM die and that didn't work well so I ended up buying a set of Hornady 375 H&H dies that has a universal seater and give it a go, it worked well.

After the initial firing of 2 rounds with 103gr H1000 under a 350smk at 2515fps i decided to ramp it up and go to some predators as I had over 350 of them just sitting there. I went from 103gr to 107gr and got some very impressive results at the end. I used the 103gr loads to get a zero at 100y and then had a guess at the velocity and bc and fired a group at 960y. When I got there I had 1 hit on the top of the target and 2 fresh holes in the backstop. I managed to dig out the predator and it was in decent shape. Pic to follow. I adjusted for elevation and fired 2 groups.

95gr H1000 350gr Predator



96gr H1000 350gr Predator



97gr H1000 350gr Predator



that's about a 3" group for a fire forming load at 960 yards.



All I can say is I was so impressed with the round I cant wait for more development but in the meantime I will be loading the rest of my box of brass with 95gr of H1000 and continue forming cases. It will be interesting to see what velocity they were doing. I had 27-28moa of elevation from 100y to 960y. I will get some over the chrono next week and let you know how fast they were going. I have a goal of 2900fps with a formed case.

A couple of the pics I posted in another thread.

[Orkan]

Interesting.

It's definitely a throwback to older case designs, which all had a problem in the case shoulder area in regard to brass growth/buildup.

I'd be interested to see how that brass behaves over a few firings. Be sure to report.

[Archaos]

I also was off doing some fire forming at a local indoor range (that was fun), I was just forming cases and not after any data, I have added a quick video to show how little the 375 Sledgehammer jumps around. I was using 100gr or AR2217 with a 300gr Sierra Game King

http://youtu.be/pb6XFpRRQpc

Seddo, I need to come down to Victoria and we can run these two DTA's side by side. That would be fun.

[Seddo]

Orkan,
I will let you know how they go. At the moment i am right into the AI look of cases. I have a 223AI, 22-250AI, 280AI and a 243AI barrel on order for my savage.

Archaos,
Its a good idea to have a shoot, i will ask and it might be possible to get you onto the farm. There is a bench at 960y, a raised platform at 1290y and they are looking at adding a 1800-1900y platform so that will make it interesting. The only downside for me is once i have finished fire forming i have to sit back and wait for my reloading dies to turn up as i have no way of neck sizing because my attempt at turning a 375H&H FL die into a 375SH neck die didnt work, its going to be a long 5 months. I will get some more 338 cases next week, i was only going to form 50 cases but now i have decided to do 100.

[Archaos]

I got a neck bushing die made by CH4D, not awsome in quality but does the job it has to do. It was cheap too.

[Seddo]

thanks for the tip, i will drop Dave an email and see what he has in stock.

[Archaos]

I use a .395 bushing, I also ordered a .390 bushing for projectiles with driving bands like the olds predators.

[Seddo]

I've had my throat lengthened, the new oal with a 350gr SMK is 3.925" so it will still mag feed. They are about 0.120" longer to the ogive than what I was loading before and not jammed.



I loaded up some rounds today with H1000 that I will run over the chrono tomorrow. I'm on a mission to get into the 2900's with the 350 SMK.

[dogtown]

2900s with 350SMK? You're starting to get into .375CT territory. Very intriguing.

[Seddo]

I had a chrono session and couldn't get past 2800 with H1000, will try retumbo next time.

I have spoken to the inventor of the round and he said he got into the 2900's with solids, so I will have to try the predators I have and get some Rocky Mountain or cutting edge.