Teach me about suppressed bolt action guns: Twist rates, barrel lengths, MOA, etc.

My pre-bankruptcy (2014) SPS tactical with a 16.5” barrel is sub-moa. I did replace the stock and trigger, but it shot sub-moa before that.

With a 16.5” barrel, my 165 grain factory federal fusions are getting 2,550 fps MV. The box states 2,700 fps. I have no idea if all the powder is getting burned, but I don’t think it will ever be a factor.

For a hunting rifle, I definitely prefer the shorter barrel.

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my simple understanding is the 20" will be more accurate at longer distances because it's simply longer than 16.5", but 16.5" can be more maneuverable.

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The advantage of a longer barrel is speed more than accuracy. Most guys that suppress are for subsonic rounds, slow pellets no sound.

You have to decide what you want to build for someone to answer that question.

1) Do you want a super quiet gun? short barrel, fast twist/heavy ammo, not longe range gun

2) Fast with sub MOA. Longer barrel, slow twist/lighter rounds. Faster but the crack will be louder. long range

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Teach me about suppressed bolt action guns: Twist rates, barrel lengths, MOA, etc.

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You don't wan to add the can length on top of a 20" barrel.

All that twist and such is a much bigger deal when running subsonic rounds, which you won't we doing.

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contrary to the boards opinion of Remington, i'm considering the Remington 700 SPS Tactical with the threaded barrel in .308.

what i'm really curious about is the correlation between caliber, barrel length, and twist rate in addition to powder burn percentage. The r700 comes in 16.5" and 20".

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here ya go brother ....
twist rate - see chart below
Rule of thumb has always been you need a faster twist barrel to shoot heavier bullets. Slow twist to shoot lighter bullets. If ONLY shooting .308 subsonic ammo, < 1125 fps., then a 1:7" to 1:9.5" twist is recommended since it will stabilize the 220 gr. bullets. If shooting both sub and supersonic ammo, a barrel with a 1:10" is best suited to stabilize bullets weighing from 125 grs to 220 grs.


.308
- 7" for heavy VLD bullets and/or subsonic ammo.
- 8" for bullets heavier than 220 gr.
- 10" for bullets up to 220 gr.
- 12" for bullets up to 170 gr.
- 14" for bullets up to 168gr.
- 15" for bullets up to 150 gr.
- 17" for bullets up to 125 gr.

barrel length
on average, you lose approx. 25 fps for every 1" shortened .308 barrel length. If a 20" barrel has a muzzle velocity of 3,000 fps .... then a 16" barrel should be around 2,900 fps. For short range accuracy out to 300 yds., a 16.5" barrel is fine. For longer range shooting, 400+ yds, the longer barrel is better since it creates more velocity to extend the shooting range. Shorter barrels are louder since your ears are closer to the muzzle, but definitely handier in the gun blind.

accuracy with suppressors
suppressors definitely effect accuracy - Barrel harmonics are altered by adding weight (and barrel length), thus changing the point of impact from a non-suppressed barrel. I doubt you will shoot the suppressor out in your lifetime, especially if shooting factory ammo.

Lastly, the Remington 700
From it's inception in 1962 to around 1995, the Remington 700 was a well-built quality produced firearm. They employed skilled machinists and engineers who valued quality over quantity. From approximately 1995 to 2005, the product began to deteriorate, and it showed in the fit and finish of rifles leaving the factory. Due to litigation, attorneys advised Remington to re-design their safety features, hence the J-lock or "wart". By 2007, Remington was a dumpster fire, and sold out to the Cerberus capitol management group. The "bean counters" made the company worse by pushing volume sales, cutting costs, and sacrificing quality control (see pic below). Shite hit the fan as Remington dissolved and was sold for pennies on the dollar.

The new owners are focused on quality control, with improved designs and upgraded features. This comes at a cost and is reflected in the pricing. The new ownership rifles are a huge improvement over the CCM produced stuff. If buying a used older 700, just do your homework and research the exact rifle (vintage) you're buying. Some of the latter produced SPS rifles are hit or miss regarding accuracy and quality.

factory Rem 700 barrel threads vs. what they're supposed to look like by a skilled machinist and competent gunsmith.

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Most guys that suppress are for subsonic rounds,

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This isn’t my experience at all.

To the OP, don’t overthink it. If ergos and weight are important to you, go shorter. If anything you shoot will recognize 100fps of velocity difference (they won’t), go longer. I do 17” on my .308s and use full power loads, factory and hand loads. FWIW, I didn’t see any POI or grouping differences with any of mine, suppressed vs unsuppressed. Sample size of 4 including pencil bbl mountain rifle that is a peach! YMMV.

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All barrels are susceptible to "flexing" and "harmonics" when adding weight to the end of the muzzle.

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I don’t disagree with that. Very good info. I was just trying to point out that with the particular rifle the OP asked about, we haven’t seen a noticeable difference in change to POI, on two separate rifles and suppressors.

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a box blind

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This is the only time I do care about barrel length. Moving around a box with a youth rifle sells a lot of youth rifles to replace the one dad stole.

You're buying the action and, to an extent, the barrel. A stock Rem. 700 isn't sexy, but it'll get the job done for most things the average person needs to do. If you need more performance, you can blueprint the action and replace the barrel later on (it'll be awhile before you shoot out a .308 barrel).

Twist rates and bullet weight need to compliment each other, but it's not like Remington slaps a barrel on the rifle with a twist rate that doesn't work well with commonly used ammunition. Can you really dial it in? Sure. Will most 168gr or 175gr BTHP work well enough with the factory twist? Sure.

16.5" is pretty short for .308 and you won't get full powder burn, which will reduce velocity. Velocity generally equates to accuracy, but mostly at the outer ranges of your shooting envelope. For long range shooting with a .308, barrel lengths typically run 24" or so, but at the ranges you're probably going to be shooting it, 16.5" is probably just fine. 16.5" is a great "truck gun" length, especially if the suppressor is on it.

Most people - not saying you specifically - can't outshoot the gun anyway, so sub-MOA only helps to the extent that it'll make up a little bit for shooter error - or at least not add to it. But for most folks, the gun isn't what gets hits/misses at 800-1200y. It's wind calls and dope. .308 isn't really the gun for that anyway - max ord for a 1000yd shot is well over 10ft. They're rainbows.

A suppressor might have a POI shift, maybe not. It's unique to THAT action/barrel paired with THAT suppressor, and THAT load. If plan A is to have the suppressor on it, then BZO and get your data with it on, then check your POI with it off. If you think the default is without the suppressor, then BZO and get data without it, and check POI with it on.

I would recommend waiting to upgrade stuff (including the trigger) until AFTER you have the best base/rings/glass on it that you can afford. That's where shooters make their money - optics. Do not cheap out on base/rings either.

Have fun with it. The Rem 700 is a fine weapon. The US Army M24 (standard sniper rifle) and many law enforcement rigs are based on it. It's gotten the job done plenty and it'll do the same for you.