Yet another .308 barrel length thread...suggestions please

[Antares]

I know there are many, many threads on the topic already and I've been though most of them, but it seems that the "perfect" length is dependent on many factors (e.g., caliber, twist rate, intended use, max range, etc.) and I don't fully comprehend all the nuance. So, I thought I'd throw out what I'm thinking about and see if I can stir up some conversation.

I have a Tikka T3x Lite in .308 with a 20" barrel (1:11 twist). I want to have it cut down and threaded so I can have my Gemtech Tracker on it full time (8" overall length). This will be a hunting rifle for brushy country so I'd like to keep it short and handy without compromising too much velocity and range. Max range will be 500-600 yards on small deer/goat sized game. I want to shoot a solid copper bullet. I'm thinking something in the 150-165gr range. I was going to start with the GMX just because I've had such good experience with the ELDM and ELDX. I don't reload. I typically shoot the 178 ELDX in my other 308, but I've read that if you switch to copper you might need to go to a lighter bullet because copper is less dense so it'll actually be of similar dimension to the heavier lead bullets...blah blah...BC...blah...blah...stabilization... As I said, I don't really know all that much about internal ballistics or reloading.

So, what's a good length for this application? I'll throw out a straw dog...tell me why 17" isn't the right choices. Assuming 0.5" of barrel goes into the suppressor, I'd be at about 24.5" overall. My other 308 has a 22" barrel plus a brake, so it's probably in that neighborhood and I don't find it unwieldy.

Thanks for you thoughts!

 

[Huskydriver]

16-18 would be fine

 

[Sniperwannabee]

can you thread a lite contour?

https://thunderbeastarms.com/pdf/TBAC_Centerfire_Rifle_Thread_Guide.pdf

 

[nn8734]

I’d go 16”. Especially considering your use case and the fact you already own a 22” 308

 

[diggler1833]

I like 18" on my .308 gas guns, but there is nothing wrong with the 16" barrels either.

You may find that bullet selection is much more critical if you actually plan on shooting at game past about 300 yards. That distance will put you around the 2K FPS mark with most bullets in the 150 range.

 

[tacops1]

I have a 16.5” .308 bolt gun

nothing wrong w it

 

[Harveyn]

16 -18 inch would be fine. Also could you please elaborate on why you're wanting to use copper projectiles?

 

[jcmullis2]

I’m sure anything over 16” will be fine. I’m pretty sure anything less could be problematic.

 

[Guns&WhiteWater]

I shoot a 16" 308 regularly with all types of bullets, but I am not aware of any bullet/powder combo that will yield enough velocity out of a 16" barrel to get a 308 hunting bullet to expand at 500 to 600 yards, if 1800-2000 fps is still the rule of thumb. 400ish yards seems to be about the practical limit, and this is running it hot. Maybe a very soft bullet would expand below this speed, but not sure how it hold up at "brushy country" ranges on game.

 

[tacops1]

308 Winchester Barrel Length and Velocity: Federal 168 grain Gold Medal BTHP

Introduction I cut back a 28″ barrel 308 Winchester one inch at a time, to 16.5″, and recorded velocity data for four different cartridges. The data was summarized in 308 Winchester / …

rifleshooter.com

 

[tacops1]

 

[Antares]

can you thread a lite contour?

https://thunderbeastarms.com/pdf/TBAC_Centerfire_Rifle_Thread_Guide.pdf

Yeah, I don't know. I guess I assumed you could squeeze 7/16-28 on there. I was planning on using a bushing to get up to 5/8-24. Anyone know?

 

[Antares]

Thanks. I hadn't seen this before.

Maybe 600 yards was getting a little greedy, but having enough juice to get out to 500 yards would be nice. Sounds like I might be better off going 18" just to preserve velocity.

 

[Antares]

16 -18 inch would be fine. Also could you please elaborate on why you're wanting to use copper projectiles?

Sure. I've been hunting with lead for 20+ years, but I'm interested in trying copper. I like the weight retention aspect and the fact that it's nontoxic. I eat a lot of deer and so do my dogs, none of us can afford to get any dumber.

I realize keeping the velocity up is even more critical when you're trying to get copper projectiles to expand properly. So maybe that's another point for going with 18". Maybe I'll end up sticking with lead. Who knows.

 

[Harveyn]

Yes seems like you're all over it. As the velocity drops you'll have more trouble getting the copper to expand reliably.

Hornady recommends at least 2000 fps for gmx to expand so assuming 165 gmx and ~ 2550 fps muzzle velocity that get you right around 300 yards.

If you can live with lead, looks like it'll be better suited for what you laid out.

Probably better to stick with heavies. 178 eldm/x would do you well. 2450 fps muzzle still gives you ~ 1000 ft lbs @600y

 

[Antares]

Thanks for all that Harvey. I guess you can't have it all, but it's still worth trying!

 

[Antares]

I shoot a 16" 308 regularly with all types of bullets, but I am not aware of any bullet/powder combo that will yield enough velocity out of a 16" barrel to get a 308 hunting bullet to expand at 500 to 600 yards, if 1800-2000 fps is still the rule of thumb. 400ish yards seems to be about the practical limit, and this is running it hot. Maybe a very soft bullet would expand below this speed, but not sure how it hold up at "brushy country" ranges on game.

Yeah, thanks for this. Just to be clear, I crawl, climb, and cry my way through brush on my way to alpine. I don't shoot through brush.

 

[Guns&WhiteWater]

Yeah, thanks for this. Just to be clear, I crawl, climb, and cry my way through brush on my way to alpine. I don't shoot through brush.

Understand. I really enjoy my little 308, mostly because when the TBAC Ultra 7 is attached, it’s still manageable when hiking through the woods. It packs a punch for such a compact rifle. But it has its limitations for long range hunting. For shooting steel, it’s a different story.

 

[Harveyn]

Thanks for all that Harvey. I guess you can't have it all, but it's still worth trying!

No problem at all. Happy to help. I'm doing a similar thing. Ended up with a Tikka lite in 300wsm 24inch. Unfortunately no suppressors down here in Australia, apparently they turn hunting rifles into silent sniper rifles.

 

[Antares]

I was seriously considering a 300wsm, but ammo selection can be pretty limited where I live so I went with 308 because it's so ubiquitous (and I already have one). I was very tempted to go that direction though. I'll post pics of the rifle once I get it cut down and put together.

Looks like it's pretty common to have Tikka Lites threaded 1/2-28. Can anyone confirm?

 

[Sniperwannabee]

1/2-28 are for 223. You need 5/8-24. You need. .725 in O.D. Minimum

 

[Antares]

1/2-28 are for 223. You need 5/8-24. You need. .725 in O.D. Minimum

Agreed. You need some meat to cut 5/8-24. That's why I'm going to have something smaller cut and use a bushing to get up to 5/8-24.

I don't think "1/2-28" are for 223" is totally accurate. I think "223 is commonly threaded in 1/2-28" would be more accurate.

My 308 Kimber was threaded 7/16-28 at the factory and its got the skinniest pencil barrel you've ever seen. Am I missing something?

 

[YammyMonkey]

I had my issued AI cut from 20 to 16, and I haven't seen any accuracy issues at all.

The GMX barrier ammo, however, is pretty lacking in the accuracy department in both 308 & 556. I would definitely buy a box & try that out before you start stocking up.

 

[Antares]

Thanks Yammy. Yeah I've gotten so used to ELDM making one ragged hole that everything else seems like it sucks...even if it's shooting sub-MOA.

I'm sort of moving away from the copper idea for this project anyway. I'd like to have reliable expansion out to 500 yards and have a short barrel 308. Doesn't seem like I'm going to be able to work copper into that equation. I'll probably see how it like the 178 ELDX after I get it cut down.

I'm still thinking 17" is a good compromise. It'll be about 24" with a suppressor. I'll probably wind up with an MV in the 2450 neighborhood and I don't think I want to go much slower than that.