Cartridge for 18" barrel?

[VikingsGuy]

I am setting up a suppressed lightweight all-around NA big game rifle. For a standard length barrel, the options are clear, but if I want something that performs well out of an 18" barrel with a suppressor it seems a little trickier selection. I need to find a balance between decent muzzle velocity and not throwing too much unburned powder/gas into the supressor.

I will be handloading so it doesn't need to have great factory options, but I will need to find brass (preferably without fire forming) and dies (preferably without having them custom made). I want to be able to use standard magazines. I will be using a carbon fiber 18" barrel and a tikka T3X action. I have one t3x action in short action that can be modded to be a long action if needed (all T3x are like that) and a t3x WSM action which therefore has a magnum bolt face as action options. Ideally, I could get a pre-fit barrel but would work with a gunsmith if necessary.

I start with a bias towards 7mm bullets (better in the wind/BC than the .30 and carrying more punch than 6.5). In the end, I want to maintain 2000fps and 1500 ftlbs at 450yds out of an 18" barrel with a suppressor attached.

What say you?

 

[T Bone]

.308, 7-08

 

[p_ham]

Short barrel= big bore.

 

[Dsnow9]

I am setting up a suppressed lightweight all-around NA big game rifle. For a standard length barrel, the options are clear, but if I want something that performs well out of an 18" barrel with a suppressor it seems a little trickier selection. I need to find a balance between decent muzzle velocity and not throwing too much unburned powder/gas into the supressor.

I will be handloading so it doesn't need to have great factory options, but I will need to find brass (preferably without fire forming) and dies (preferably without having them custom made). I want to be able to use standard magazines. I will be using a carbon fiber 18" barrel and a tikka T3X action. I have one t3x action in short action that can be modded to be a long action if needed (all T3x are like that) and a t3x WSM action which therefore has a magnum bolt face as action options. Ideally, I could get a pre-fit barrel but would work with a gunsmith if necessary.

I start with a bias towards 7mm bullets (better in the wind/BC than the .30 and carrying more punch than 6.5). In the end, I want to maintain 2000fps and 1500 ftlbs at 450yds out of an 18" barrel with a suppressor attached.

What say you?

Following! Eventually I want to do something similar.

 

[Fire_9]

.308, 7-08

A .308 with some absolute hammers was my first thought

 

[Don Fischer]

Hum. Sounds like your trying to cut your own throat. 18" barrel's I simply don't care for, other do. But if you get something that use's a slow powder then maybe a fouled suppressor should be expected. Sometime's what we want can take a lot of experimenting to find and other time's it simply eludes us. I had a 20" barrel on a Mod 660 in 308, my son somehow ended up with it. That was one really nice rifle to carry around and shoot! I think the problem you'll run into is talking about an all around cartridge suggests to me either a 6.5 or 7mm and up. never shot one but I would think a 7mm-08 would work well but I consider a 20" barrel. Suppressor may or may not work? Other than the 308 case and 30-06 case I don't see a lot that intrest's me for an all around cartridge in N.A. I don't like magnums! I wonder if that short 270 has come out yet? Supposed to be a military cartridge and might be friendly to faster powder.

 

[Deleted member 16014]

Vanilla .280 with 162 eld-x or 168 vld should get you there.
Was thinking .308 too but it might be tough to hit your 1500 ft lbs benchmark at 18" 308 win velocities.

 

[winmag]

The suppressor will give you some extra velocity above a regular 18" barrel. I'd just do a 7mm-08. 7SAUM or 7WSM will absolutely get you past 450 yards.

A long action cartridge will just eat up bore length. Stick with short and fat, or just short.

 

[brockel]

I’d roll with a 7mm saum

 

[cahunter805]

I agree. 7SAUM with 18” barrel is the way to go.

 

[brockel]

Can’t remember where I read it but a few guys running 17” barreled 7mm saums we’re still pushing 162 grain eld 2850fps

 

[MLaird]

I'm looking at doing something similar, but with a 20" barrel. I was thinking a 6.5CM or 7mm-08. I talked with my gunsmith and he has a Savage 6.5-284 action that I could use so I'm thinking about that now as well. If I go that route I'll get a 7.5 twist barrel and shoot the 129 Absolute Hammer.

 

[VikingsGuy]

Lots of good thoughts. A few follow-up questions:

Would 7SAUM throw too much unburned gas/powder at 18"?
Would the 7SAUM fit a WSM action?
Would .284Win be an option between 7mm08 & 7SAUM?

 

[Ben Lamb]

Go medium bore. 8mm mauser at least.

 

[VikingsGuy]

Go medium bore. 8mm mauser at least.

Would make a splash with the 7.62mm suppressor I already have

 

[Ben Lamb]

Would make a splash with the 7.62mm suppressor I already have

You're getting the quality of advice you're paying for, pal.

 

[winmag]

Would 7SAUM throw too much unburned gas/powder at 18"?
Would the 7SAUM fit a WSM action?
Would .284Win be an option between 7mm08 & 7SAUM?

No
Yes
Yes

 

[winmag]

[Insert someone saying 7mm Sherman Short Mag is the best cartridge ever invented]

 

[VikingsGuy]

I think 280AI is ballistics twin of 7SAUM, any reason to prefer one over the other in a suppressed 18" barrel? I ask as I already have brass and dies for the 280AI.

 

[noharleyyet]

.308, 7-08

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