First, how does the Noveskes polygonal rifling compare to traditional rifled barrels?

 specifically is it worth the extra cost? and if so why dont other manufactures do the same?

and next, without going into weight or length, which length gas system is better?
does a longer dwell time help with stabilization?


Thanks
Rob

What will be the purpose of the weapon?

J

whoops, sorry

I am slowly planning a SPR type build as time and funds permit,

looking to effectively engage evil zombie paper targets out to at least 600 yards as that is the longest range I have access to

and with whatever barrel design it will be a slower twist for the heavy stuff, nothing under 69 and hopefully some 77 hand loads

Thanks
Rob

Honestly, the quality of the barrel is far more important than the design of the rifling. Noveske barrels are accurate not because they're polygonal, but because they're well made. A quality barrel will shoot well, and a poorly made barrel will shoot poorly. I think you'll find that there are a number of places to get barrels whose accuracy will very high.

You need a faster twist for heavier loads 1in7 or 1in8  and slower twist 1in9 or 1in12 for lite stuff.

ok this is the 2nd time ive seen this today.  1/7 is FAST twist.  1/12 is SLOW.  You want faster twist for heavy stuff.  Its one full turn in 7"(1/7) .


the polygonal rifling is supposed to increase velocity.

The polygonal rifling is supposed to offer a better seal between the projectile and bore resulting in increased velocity.  In the real world, the difference is usually negligible and may not be worth the added cost for you.  Noveske barrels are expensive and there are barrels that will shoot just as well, if not better, for less money.

The biggest question is whether you are up to the task.  Talking about shooting accurately at distance is one thing, actually doing it is another.  I learned that the hard way.  If you want an SPRish build, it's going to depend a lot on your preferences.  Actually, I've been shopping for a barrel for a build that I'm getting ready to start.  Just waiting for the funds to show up.  I just build a "field" precision rig, and now want to build an all out precision rig.  This is my shopping list.

BCM SS410 18" barrel - I'm going with this barrel because I know they are good and very reasonably priced.  I don't plan on single loading really heavy bullets and will load everything to mag length, so the 1:8 twist is fine for me.  It has a rifle length gas system, which will offer smoother operation.  I'm not worried about the reduced dwell time because I'll only be shootng full power loads out of it.  My 16" middie build based on this barrel shoots sub MOA, so I figure that the 18" should too.

Vltor MUR upper receiver - I'm using this, well, because I've never done so.  They are supposed to be "it."  Tight tolerances so there isn't too much slop in the operation of the bolt group.  Everything should stay in line, promoting accuracy.  This upper is also supposed to be really rigid, also promoting accuracy.

BCM bolt/carrier group - just because I'm a fanboy.  Good bolt group.

Spike's lower receiver - because they are built well, show clean machine work and I think the Spider with the red color fill looks really cool.

Geissele DMR trigger group - I don't think I need to explain this choice except to say that I prefer a two stage on a precision rig.

Magpul PRS - It's a good stock and I don't have one right now.  This recoil system should work nicely with the rifle length gas system and you can get that neat mono pod attachment for it.

Bushmaster free float tube - I use these tubes because they are light and comfortable.  I have no need for rails on a build like this.  The bushmaster tube uses a really thick nut which helps with rigidity.  It also comes with a bipod stud installed.

I think that this will be the makings of a tack driver.

sorry for the confusion about barrel twist, I didn't think things through all the way when I posted

preferably I want a 1 in 8 twist to mimic my HP rifle so I can maybe keep my hand-loads as simple as possible,
and yes I know that just because the twist is the same doesn't mean that they will shoot the same in each rifle

As far as my ability, I have a back ground of shooting HP, I'm comfortable behind a rifle

and So far all I have is a RRA upper receiver, so Ive got lots of options to play with, but a MagPul PRS stock is going on this rifle

What hand loads are you running?  If it's anything like one of the "standard" loads, like 24gr of RE15 or Varget under a 77gr SMK, any of the barrels mentioned will likely shoot it well.  Really, I don't think I've seen a rifle/barrel that didn't at least shoot that load well.  If you're shooting heavier and single loading, I can't comment.

If I recall correctly I was running 24.5 RL15 under a 69 SMK for short and mid range and single loading 80 grain SMK's for 600

but I was planning to turn too 77 or 75 grain bullets for my short and mid range to avoid having to single load for this rifle

24.5 RL15 under the 69gr SMK is the load that I run for short distances.  Well, actually, I've been playing with 24gr and am going to try a new batch out this weekend.  I'm hitting around .5MOA groups with it at 100 yards.  I've found no need to go to lighter flat base bullets with that kind of performance.

In any case, from what I've seen, shooting 69 or 77 SMKs loaded to mag length with RL15 or Varget is sort of like parfait, because everybody likes parfait.

Good luck.

.5 MOA is what I would strive for,
I have never been able to shoot better than about a minute when I did HP

So is there any opinions on the length of the gas system as far as accuracy is concerned or was my original theory correct?

Sorry, missed that thing with the gas system.  The gas system that you go with will have no effect on accuracy.  What it does affect is the perceived recoil impulse.  Essenstially, the longer the dwell time, the harder the kick.  That's why guys going with 18" barrels like rifle length gas systems and guys going with 16" barrels like mid length gas systems.  Shorter dwell time leads to smoother shooting, which may affect accuracy indirectly.  I do know that I get back on target faster with a gas system with a shorter dwell time.  The only drawback to a short dwell time is that the rifle may short stroke with under powered ammo, like Wolf, but that shouldn't be an issue with a build like this.

I've gotta qualify my statement about half MOA groups.  To date, I've been able to do that with 69gr ammo at 100 yards for five shots.  I'm not that good a shooter and I'm using a sandbag in front with a squeeze bag under the butt when I shoot these.  My groups get appreciably bigger when I'm using nothing but a bipod and my hands, but I'm still working on it.

If you're thinking about an 18 or 20" then I'd go with a rifle length gas system.    If its a 16" then I'd go with a mid-length.  I agree with TonyAngel... this doesn't affect accuracy.

I have 1:7, 1:8 and 1:9 barrels (on different lengths).   Personally, I like the 1:8 best..

I have a Noveske 16 and a Rainier 18... I get slightly better groups with the Rainier.

That's good the hear about the Ranier.  I'm starting a new build and was going to go with another BCM barrel, but have the itch to try something new.  If I do try something new, it might be something other than a .223/5.56.

What ammo are you shooting out of your Ranier?