300WSM - Barrel Length Decision - How Short?

[AKMoose]

Have a Tikka in 300WSM. I will be shortening the barrel as I am sick and tired of snagging on brush constantly, and I think I get more than enough speed/power out of this thing to cut some off the barrel and not miss much.

I know I will lose speed, but how much? Stock barrel is 24.3 inches and I have an APA "The Answer Brake" on it bringing me out to 26" currently.

I picked up a TI Pro Tiny Brake from Salmon River Solutions that I plan to switch to (shorter and not self timing, therefore lower profile). My current thought was to go to a 20" finished length barrel with muzzle brake (so barrel would be about 18.5").

Appreciate any input you guys have about if this is a stupid idea, and for those that have done this, how much speed I should expect to lose.


*Note that I do have an extra tikka barrel, so if it shoot like crap or I lose a ridiculous amount of speed I can always swap back to full length.

 

[Ryan Avery]

What bullet?

 

[PantherCity]

If you have a chrono you could always chop it down yourself an inch at a time until you get a speed you can live with then take it to your smith for him to put on a proper crown, thread and time your new brake.

Hacksaw would work but a chop saw or even angle grinder would go faster.


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[AKMoose]

What bullet?

Currently run the 178gr ELDx. Also considered the bondstrikes from norma.

Open to options there too. This is my do it all rifle

 

[Ryan Avery]

I built a 20" shot 200 grains at 2830-2850. It shot 185 Juggernauts at 2940.

Juggs would be my choice. Great killing bullets and with an Ok BC.

 

[AKMoose]

I built a 20" shot 200 grains at 2830-2850. It shot 185 Juggernauts at 2940.

Juggs would be my choice. Great killing bullets and with an Ok BC.

Okay thats pretty sweet velocity. My stock tikka barrel I was struggling to get 3000fps with the 178's with a full length barrel. Going all the way down to 18.5 I was expecting to drop around 2850ish - seem reasonable? 5.5" chopped = 150 fps loss.

 

[Hthunter]

180-200 grain .308 bullets coming out of a suppressed 18-20” barrel ~2800 fps is a pretty badass setup.

 

[Formidilosus]

Currently run the 178gr ELDx. Also considered the bondstrikes from norma.

Open to options there too. This is my do it all rifle

It’s always the same- 20-30cal per inch. There is no magic.

 

[Deerfield]

I built a 20" shot 200 grains at 2830-2850. It shot 185 Juggernauts at 2940.

Juggs would be my choice. Great killing bullets and with an Ok BC.

Ryan, was your 300 WSM a SAAMI chamber or did you have it throated out a little?

 

[Blackdog317]

I have a short 300 WSM from Hell's Canyon Armory that is built off of a Tikka action. 20" barrel with a long throat.

The 180 gr Norma Bondstrikes averaged 2905 fps over a Labradar as I was fire-forming brass. The box lists the velocity at 3085 fps (probably from a 24" test barrel).

I am finishing up a load with the Barnes 175 LRX over H4350 now. While testing different charge weights at the upper end of book max, I am right around 3000 fps.

 

[AKMoose]

It’s always the same- 20-30cal per inch. There is no magic.

There is a cutoff somewhere (or a change to the curve), otherwise that would mean cutting down to 10" would mean i still get 2550fps. Or cut to 5" I would get 2400fps. The curve is pretty well defined from 24" to 20" but pushing below that it's less exact.

 

[Formidilosus]

There is a cutoff somewhere (or a change to the curve), otherwise that would mean cutting down to 10" would mean i still get 2550fps. Or cut to 5" I would get 2400fps. The curve is pretty well defined from 24" to 20" but pushing below that it's less exact.

I’ve had them down to 17”, and buddys have had them at 16”. I’m not talking “I like, I think, I feel”, I’m referencing dozens and dozens of barrels.

 

[AKMoose]

I’ve had them down to 17”, and buddys have had them at 16”. I’m not talking “I like, I think, I feel”, I’m referencing dozens and dozens of barrels.

I didn't think you were, just saying that it's not down to 0" that it's 20-30fps. Glad to hear you've seen that trend down to 16" though, that's helpful data!

 

[westernarcher]

Not a 300. But I had a Tikka factory 24" barrel in 6.5 CM and replaced it with a bartlein barrel cut to 19". Only lost 100 FPS.

 

[Beckjhong]

18” x bolt here. I get just under 3000fps on a 165gr copper mono

 

[Chris_in_Idaho]

I built a 20" shot 200 grains at 2830-2850. It shot 185 Juggernauts at 2940.

Juggs would be my choice. Great killing bullets and with an Ok BC.

Can I ask what powder you're using with the 200s?

 

[z987k]

If you throat the chamber a little, put in a long action bolt stop and use the right powder, you can probably get all of the speed back from the cut barrel vs what factory ammo can do in the longer barrel.

 

[Mangata]

Honest question that I have not seen addressed in the barrel length conversation.

Should you change your rate of twist in shorter barrels to preserve accuracy??? Should a shorter barrel have a faster rate of twist since the bullet has less time in contact with the rifling to spin it??

Thanks in advance!

 

[z987k]

Honest question that I have not seen addressed in the barrel length conversation.

Should you change your rate of twist in shorter barrels to preserve accuracy??? Should a shorter barrel have a faster rate of twist since the bullet has less time in contact with the rifling to spin it??

Thanks in advance!

No. While there is a minor correlation because the rpm of a bullet is dependent on velocity and velocity drops with shorter barrels, it's much more dependent on twist rate. 1-200fps isn't going to make much difference with stability. Atmospheric pressure plays a bigger role.

 

[msstate56]

I’m quite happy with my 20” 300 WSM 1-10 twist with factory Hornady 200 eldx