Accuracy change after Barrel cut down

[Cnewhouse48]

I recently had 2 barrels cut and threaded from 26”-16 and 24-16 one a 223 one a 308.
Both of these guns are factory savage barrels that consistently shot .75-1moa. I’m now seeing HUGE changes in accuracy.

I’m pretty sure it’s just due to harmonics change/ bullet stabilization. I have several hundred loads for each rifle that I made before the cut down, now those loads don’tgroup well.
Is this a typical issue after cutting that much barrel off?

 

[hafejd30]

Yes

You changed harmonics as you already know

You messed up the tuning fork

You’ll need to tweak the loads

 

[Cnewhouse48]

Yes

You changed harmonics as you already know

You messed up the tuning fork

You’ll need to tweak the loads

that’s what I figured. Thanks.

a 16” suppressed gun vs 24/26 is well worth the new load data!

now I need some projectiles...

 

[hafejd30]

It will most likely shoot the current bullets yet. Just need to play with the powder charge

Keep in mind you’ll loose a ton of velocity with the shorter barrel. So recheck your ballistic data after finding a good load

 

[Cnewhouse48]

I shot some today from my pet load and lost about 130fps which I was expecting.
I’m seeing 2750 with a 75 gr eldm out of a 223.

I’m going to try xbr8208 and pp2000mr hoping for more velocity. I’m currently using Varget.

 

[hafejd30]

I’m sure your well aware already but test the new loads without the suppressor first. Just to make sure they stabilize before sending through your can

 

[Cnewhouse48]

Yes sir thanks for the reminder though.

 

[Glock talk]

Although not a cut down or a bolt gun. I swapped barrels in my lmt mws from a 13.5 with flash hider to a 16”. I had previously been shooting 168smk with 42.0 gr of IMR 4064. The 16” shot them better (.6 compared to .8)

 

[Dthomas3523]

Should stabilize and run the same powder charge fine for the most part.

Group size is more affected via seating depth. Though that much of a reduction in barrel and powder may need slight tweaking. Likely not much though like seating depth will.

 

[NWnewguy]

That's a serious haircut on those barrels!

I cut down a 6x47 barrel to 17" and wished I had gone to 20". The thing is loud with a can on it now. Plus the velocity loss, I don't see much benefit other than handiness to cutting barrels very short. I guess that's why we all need some of each!

 

[Cnewhouse48]

Man a 26” gun with a can in a deer blind isn’t worth a shit. I’ll build a couple more long barreled guns for target guns.