Who reloads for a 1:10 twist Swiss arms?

aric84

aric84

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Been trying to find a good load for a new to me Swiss arms but have been having trouble getting anywhere.

My old AR load was 24.5 gr BlC2 pushing a 69gr SMk, worked great in the 1:7 but seems to be iffy with the 1:10. About 2" to 3" groups at 50yds. I think I will either try a hotter load to get the RPM up to stabilize better or go to a lighter bullet.

I had some other loads that were just thrown together with 55gr Hornady btfmj and they seem to shoot a bit better but not stellar, about 1.25" at 50 yards.

Strangely the best group was shot with an old batch of XM855 5.56 that has shot like crap in all my other guns, it grouped 10 rounds under an inch at 50 yards.

I pulled a bullet from the XM855 (ss109) and compared it to the 69gr SMK and the bullet length is the same so I figured it would stabilize just like the ss109 projectile. I am wondering if the added mass on the SMK and therefore lower velocity is affecting the groups.

My next outing I am going to try some different 69gr loads and also some of the 55gr SMK's when I get a box in.

Anyone have a good load that they have settled on for their Swiss Arms?
 
No need to reload when someone has the 63gr Ruag ammo in their inventory. It was tested to be perfect for that rifle barrel with twist.

You may find a load that's as tight but the Swiss Defence Force beat you to it!
 
I'll have to check it out, though I do still want to load for it, I have thousands of pieces of brass and a good availability of bullets to choose from.
 
I'm hoping so Ganderite, I was figuring if the bullet lengths are the same then the twist rate should be okay. I'll definitely try different seating depths and various powder amounts.

Which is better to play with first, OAL or powder charge?
 
I've got IMR 4895 on hand as well as IMR 4320 which may meter better through my progressive(RCBS pro2000). I'll give them both a try and report back here.
 
J996 said:
I've had mine for many years now, older green rifle 1:10. It loves XM193.
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I may have some of that laying around and if not it should be close to the same as the American eagle black box stuff that is widely available. Thanks for the tip.

On a related note, when I pulled apart one on the M855 rounds it looks to be loaded with a ball powder that looks a lot like BLc2 or H335. Some food for thought in my load development.
 
aric84 said:
I may have some of that laying around and if not it should be close to the same as the American eagle black box stuff that is widely available. Thanks for the tip.

On a related note, when I pulled apart one on the M855 rounds it looks to be loaded with a ball powder that looks a lot like BLc2 or H335. Some food for thought in my load development.
Click to expand...

The factory loads with 844, which is commercially sold as H335, although the speed of the lot in your ammo could be different than commercial powder speed.
 
rather than asking for " what will work " you should develop a reloading technic yourself, does not matter if your running a gas drive or a bolt gun, the process is the same
its a science experiment, but its not rocket science... its actually pretty simple to tune any gun if you got a good process for load development
 
Grant Shave said:
rather than asking for " what will work " you should develop a reloading technic yourself, does not matter if your running a gas drive or a bolt gun, the process is the same
its a science experiment, but its not rocket science... its actually pretty simple to tune any gun if you got a good process for load development
Click to expand...

Never hurts to find a baseline though for a particular rifle. I have been reloading for quite a while now so I know plenty about load development for each rifle that I have.

So far from other reports from Swiss arms owners, it seems to have a preference for the NATO spec ammunition, and learning the it is Loaded with a bulk grade similar to H335 give me a great starting point.

These are great guns and have a good accuracy potential. With so many out there, why reinvent the wheel if there turns out to be a common load people are using.
 
I'm noticing a pattern around the H335 burn rate when checking around online. I may grab a pound of that and some 8208-XBR which is very close and should meter well, see what the results are.

I did use the berger twist rate calculator and it shows the 69 grainers to be in the upper range of marginally stable when pushed hard enough. I'll try them out along side the 55's and compare accuracy.

Thanks for all the help guys, I'll make sure to report back.
 
I've tried out 69 gr in my Black Special and never had much luck. I've gotten good results with 55gr Hornady fmj over 26gr of Varget.
Someone gave me a couple hundred Speer 45gr soft points that are starting to show promise as well.
 
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