.204Ruger projectile advice saught

[aqualung]

Hi everyone, I'm after a bit of help and advice...
Shortages of certain (make that most) projectiles in UK means that I am unable to source 39grn Sierra Blitzkings for my .204Ruger.
Fortunately I have a metric shit-ton of 40grn .20cal Hornady V-max.
Unfortunately I cannot get them to shoot out of my Howa1500!
I'm getting consistent 0.3MOA groups with RS40 powder and the 39grn Blitzkings, but even with the same load, the 40grn V-max doesn't go into less than an inch.
I've tried changing powders, seating depth, primers... all to no avail.
Does anyone have the secret sauce to get these bullets to shoot accurately?
Powders are quite limiting in Europe, with most Hogdon powders being banned. Obviously we have access to Vihtavouri Reload Swiss, Lovex etc.

The Blitzkings shoot well at SAAMI length, but do I need to jump the V-max a certain amount? I think the freebore is too long to jam them...

Any/all help and advice VERY gratefully received. Thanks.
N

 

[6AYoteHunter]

Your twist rate might not be fast enough at your elevation for the 40 gr vmax. The only thing you could try is to find a higher node where maybe the bullet can be fully stable at higher velocity. My factory remington 204 shoots the 40 gr vmax best but the twist rate is about 1/4" faster. Have seen some rifles 1/4" slower and can never get that bullet to group at lower speeds or elevations. Hornady should have used a slightly faster twist when they spec'd the design.

 

[RegionRat]

What is your barrel twist?

You will want a 1:10 Twist to be able to go to sea level with impunity.

At the 10 twist, the SG will be in the neighborhood of 1.6 at 3600 fps.

By the time you are at 12, you will find that SG has dropped to roughly 1.1 and is marginally stable at best (SG of 1.0 is unstable).

Other than the twist, there isn't a reason I can think of where a gun that likes the Sierra 39 should not be able to also shoot the Hornady 40 at least decently.

I have lots of experience with both of these two bullets across many different rifles including bolt guns where depth is tuned as well as AR platforms where they are loaded to magazine length and they have to jump. No issues either way.

The only instances where I have seen really bad performance was in slow twist barrels, and the fix for those was to limit those guns to the lighter shorter bullets.

Based on that, I suspect you may be on the edges of stability and seeing where one design holds stable and the other may not, and even see the difference on days with different Density Altitude.

I would suggest you give the rifle a thorough inspection just to be sure, then see if you can go up to the highest available place you can use to test. If the twist is really 12, you can save yourself the trouble, but if it is 10 then it is possible the rig needs work. Good Luck.

 

[supercorndogs]

Sometimes a barrel just doesn't like a certain bullet.

 

[aqualung]

Thank you for responding, Guys. Much appreciated.

I found some 40grn Bergers I'm going to try.

I also checked the ACTUAL twist on my barrel, not just what the factory says. It is (as accurately as I can measure) 1:12 1/4, so that may be the issue.

Just have to wait until Sierra runs a line of 39grn Blitzkings, or shoot the bergers...

Again, thanks for your input, Guys.