Promising results with Berger 70gr VLD's in Swiss Arms

[Ar180shooter]

So I was testing out some loads for my Herron rebarreled Swiss Arms Carbine using 70gr Bergers. I found light loads (less than 1 gr off starting) grouped atrociously (we're talking 4-5" 5 shot groups). As the loads got hotter, things tightened up. At 0.2gr off max load, I found the sweet spot. 5 shots in 0.6" @ 100 yards. Naturally I'll have to reproduce this before I can say I have a decent load, but what I have so far goes as follows:

Winchester brass
Federal AR match primer
23.3gr Varget
70gr Berger VLD match
2.280" COAL (the Swiss Arms mags can accomodate slightly longer cartridges than a STANAG mag can).
Moderate factory crimp

 

[gps2]

Curious if you're weighing your brass? I have found win brass to be consistently inconsistent.

 

[bearhunter]

If you have a 1-12 or 1-14 twist rate in your bore, that bullet will be to long to stabilize.

I don't know what your rebarreled Swiss Arms Carbine had for an original twist rate but only you can tell us what you have now. From your other posts I know you are knowledgeable so likely all is well.

I loaded the same bullets into Winchester cases over a similar starting load to yours of H335 over CCI small rifle magnum primers. The accuracy wasn't as bad but it certainly wasn't good either, around 2.5in at 100yds.

It wasn't until I got to 25 grains of H335 over CCI small rifle magnum primers that accuracy became what I expected of this bullet. My rifle is a Tikka T3 with a 1-8 twist and a 24in bbl.

I started to get flattened primers at 25.1 grains so backed off to 25.0 grains of H335. Accuracy never changed. My groups stayed around .6 moa depending on how well I held the rifle and kept track of parallax.

Those Berger VLD match bullets are great but they certainly like to leave a lot of jacket fouling behind.

My suggestion is to bump up your load as long as it is operating properly.

IMHO, the brass would have to be extremely inconsistent to give such a broad group. Have you checked the run out??

 

[Ar180shooter]

I forget what the original was, I guess I should check as I still have it laying in my safe, probably a 1:10. The rebarrel is a 1:8 match barrel with .223 Wylde chamber.

I was surprises they did so poorly close to starting loads. The twist is more than suficient to stabilize the bullets, however I have found with the 3 other Swiss Arms I've owned that they can be finicky with which loads they like and which ones they don't. Considering how the groups tightened up as the load increased (the load that did 0.6" was 0.2gr off max load according to my Berger book), I'm thinking it was the powder charge. The COAL, brass and primers were the same across all loads tested (basically going from min to max load in 0.2gr incriments).

Part of the reason why I am usin Winchester brass is because when shooting in SR competitions, it's difficult to recover your brass, so I have to essentially treat it as disposable, and I have a few thousand Winchester brass lying around. If I can get a good consistent load developed, I won't be heartbroken if I can't get my brass back. I've used it before using Hornady V-Max bullets and BLC-2, and have had quite good results, and not nearl the huge spread experienced with the Bergers on my start loads.

If my load can maintain it's grouping size, I wouldn't mind pushing it up a little more (since I'm seating the bullets a little farther out than the book I should be able to go a little beyond max safely), but I should still be getting between 2800 and 2850fps with my current load, which is more than acceptable.

 

[Grawfr]

I've seen his rifle and that's one sweeeeeet little number. I'll be really curious to see how the hotter loads will perform. Keep us posted, Ar180shooter!