I realise that the 1x7 twist allows you to stabalise heavier bullets. Are there any andvantages of a 1x9 over a 1x7?
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I realise that the 1x7 twist allows you to stabalise heavier bullets. Are there any andvantages of a 1x9 over a 1x7?
It's my opinion that you're only gaining a marginal increase in accuracy at the expense of being able to shoot any type of ammo.
Your 1x9 might shoot 75 & 77 grain ammo, might not.
Your 1x7 will shoot anything. Period.
The 1x9 twist holds the same place in my heart as 16" carbines with M203 cuts...
Zydeco,
Might I also suggest that you use the search function and look at some of the posts here. Much of what you are asking has been talked about here many times over. Just a thought.
1:7 here.
It's just depends on the rifle... some 1/9" barrels can shoot up to 75's, some can't. Some are a bit more than 1/9, some are a bit less... My S&W M&P15T has a 1/9", but it actually measures out to be 1/8.8", and can shoot 75's just fine, haven't tried anything heavier though... it thrives on 68/69gr. loads though. It actually shoots the 75gr. Hornady Match BTHP's better than it does 55gr. V-Max/B-Tip/FMJ's.
If ALL you're going to be shooting is 75/77gr. bullets, get a 1/7, but if you want to shoot anything from 40 - 75gr., get a 1/9". My brother has a Colt LE6920 that my S&W just eats alive when comparing them with accuracy - he just bought himself a Noveske N4 16" that's just the sweetest carbine I've ever seen - and I'm going to be comparing it head to head this weekend, weather permitting - I don't expect to have better accuracy, just want to prove that you don't need a $2000 rifle to get sub-.75 MOA groups. IMHO, the BEST twist rate for the AR15 is 1/8", but unfortunately, it's hard to find any 1/8"s except for in heavy contour SS varmint/target barrels.. If there is a chrome lined 1/8" barrel thats either 16 or 18", someone please tell me!! :D
Check out these groups I shot yesterday doing some load development.
The 10 shot group on the top left is with 69gr. Sierra Matchkings.
The 10 shot group on the top right is with 68gr. Hornady Match BTHPs.
The 8 shot group (didn't have 10) on the center is 75gr. Hornady Match BTHPs.
http://i261.photobucket.com/albums/i.../Target_02.jpg
http://i261.photobucket.com/albums/i.../Target_01.jpg
All these groups were using my S&W, rounds loaded with various weights of Ramshot TAC, using CCI Small Rifle Magnum primers, and Winchester brass, loaded to a C.O.L. of 2.614" for all rounds. Shots were made from the prone position, off my Harris BRM bipod, at 100 yards, 60 degrees, no wind.
http://i261.photobucket.com/albums/i...747/MP_IOR.jpg
My Noveske is a 1:7 and it will easily nail stuff out to 200 yds. with 55gr. ammo. It also shoots the heavier ammo without a problem. Unfortunately, I don't have any cool guy data or targets to show off. But, I feel confident with 1:7.
Iraq I did look around a little albiet not in depth for the answer for my question. Usually twist rate questions are what weights can I shoot in what twist etc.... I am trying to find out if there is ANY advantage to having a 1x9 over a 1x7. You see the franken upper problem child in my other post is my paractice and three gun match upper. I will be building a serious upper aswell. I currently hace 2 uppers. One is the Franken upper and the other in a 20 inch HBAR bushy. I love the way the HBAR shoots. That kind of accuaracy with M193 out of chrome I did not believe was possible. However as I am sure you know it weighs as much as a SAW and handles like a sldge hammer. Definately sucks for 3 gun. So the franken upper is my education and practice upper. I want to build another carbine upper that I would bet my life on. Ofcourse I need to be able to afford it.
If you ammo is warm or you reload it that way and depending on barrel length, you can stabilize the heavy bullets in the 1n9. No sense in my opinion hot rodding the stuff to work if you don't have to. I would say go with the 1n7 or stay with what you can safely shoot with the 1n9.
I spent more than one occasion with my 10.5 LMT ringing the 12x12 at 400 with irons and 55 grain ball. I've also spent some time with 262 in a 1n9 Colt 20" shot it moa.
It was 400 feet!---no yards, I mean.
No it was 400 yards, in theory, that's 3 moa, nothing to brag about. Just mentioned it to say that the 1n7's will shoot the 55 grain ball fine.
It was 10 moa of drop with that short barrel, no worries with the LMT fixed rear, dial it up!