Straight Pull AR15 Spec

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[ARCHIVED THREAD] - Straight Pull AR15 Spec

Posted: 2/12/2007 1:37:36 AM EDT

I was wondering if anyone had a suggestion for a spec for straight pull AR-15. I'd be mainly using it for general fun range shooting - typically 100/200/300 meters. Not a lot of competition shooting, maybe a bit of civilian service rifle and ETR. While I do some reloading I'd also want to shoot surplus RG ammo and not have any extraction issues.

Posted: 2/12/2007 1:40:22 AM EDT

[#1]

Vultures inbound

No, j/k, actually there are some very helpful and knowledgable chaps on here, but I'll leave you to sort out

which ones they are

Posted: 2/12/2007 11:52:30 AM EDT

[#2]

Quoted:
I was wondering if anyone had a suggestion for a spec for straight pull AR-15. I'd be mainly using it for general fun range shooting - typically 100/200/300 meters. Not a lot of competition shooting, maybe a bit of civilian service rifle and ETR. While I do some reloading I'd also want to shoot surplus RG ammo and not have any extraction issues.

How much do you want to spend, and what style are you after?

With what you have said, pretty much anything from 14.5" to 20" barrel will work...

Do you want to have a side charger, or just use the standard T handle at the back?

Personally for that requirement I'd have a 14.5" flat-top carbine with a side charger conversion. If you plan on doing much Civ SR (vs the plinking & ETR), then a longer barrel would probably be wise, so in that case I'd have an 18" flat-top with a fixed stock and a side charger conversion...

Posted: 2/12/2007 12:24:46 PM EDT

[#3]

I used to have a SGC 30 cal and when the side charging handle worked it was great - but the actual handle tended to work loose even with locktight and end up gouging the upper. Is this the bane of all side handles, or are some better made ?

For price I'd probably spend upto 1k.

So for reliable RG extract would I need to specify a 5.56 chamber and avoid tight match .223 chambers ?

Posted: 2/12/2007 12:52:45 PM EDT

[#4]

Things must have come a long way since the days of side cocking handles coming loose.....

.....

I have to swing on mine to get the buggers loose.... Must have been a earlier "jabba" affair?

Posted: 2/12/2007 12:58:12 PM EDT

[#5]

You won't get a side charging AR for less than 1K unless it's 2nd hand.

The cocking handles I make are located with a dowel and don't work loose.
They also only have one fixing screw

Also, the reamer I have had most success with is a .223 match but it has no problems with surplus such as RG.

Mark

Posted: 2/12/2007 2:02:32 PM EDT

[#6]

With the benefit of hindsight I shouldn't have bought the SGC's 20" heavy fluted barrel version. It was fine off a bi pod at 500/600yds but real pain (literally) to use standing / unsupported positional in civ SR comps, especially if you're a wimp like me. 16" h-bar will do 300/400yds no problem, right cocking handle a must if you're right handed, tac-latch optional IMHO

Posted: 2/12/2007 2:46:31 PM EDT

[#7]

Quoted:
With the benefit of hindsight I shouldn't have bought the SGC's 20" heavy fluted barrel version. It was fine off a bi pod at 500/600yds but real pain (literally) to use standing / unsupported positional in civ SR comps, especially if you're a wimp like me. 16" h-bar will do 300/400yds no problem, right cocking handle a must if you're right handed, tac-latch optional IMHO

You're absolutely right about that, Old fella

.
Unfortunately, SGC were the only player in town for a while and they only sold one model of AR, the bull barrelled, fluted, ambi side charger.
Some of us knew there was a different way and the HBar barrel was far more user friendly (It still is). God knows the amount of Bob's barrels I've reprofiled

Anyhow, i've used a HBar for several years (still have one) and use it when I feel there is a need, but that's probably more due to barrel length.
For fun stuff, I use my 14.5" carbine but for anything meaningful I use the 18 or 20" rifles.

The 20"HBar is a good profile and when made correctly, is very accurate. It is a full 1" under the handguards and with this barrel and a scope, my PR rifle weight 12lbs. That's with a DCM float tube.
The 18" barrelled rifle has a diameter of .850" (SPR profile) under the handguard (That's a Daniel Defense railed handguard) and that rifle weighs only 9.5lbs with the same scope.
The 20" rifle has a slight advantage at 600yds though which is probably due to velocity, butn the 18" SPR could probably be consdidered more useful, but for a do-all rifle, I'd go for a 20" version every time.

Mark

Posted: 2/12/2007 11:50:46 PM EDT

[#8]

Well there is ONE advantage to Fat Bobs 1" bull barrels…

…if you ever need a really strong pry bar your in like Flynn!

ANdy

Posted: 2/19/2007 3:51:54 AM EDT

[#9]

I've been looking to purchase an AR15, keeping my eyes open for some second hand bargains…… not that there’s many about. Which has lead my quest to look at a new one

I’ve been looking to get a rifle that fine for target work, fig 11 and may be PR for upto a max of 500-600 yds and so far I’ve been specking up 20” barrelswith the go fatsder bits. Whats I'm stuggling to find out is how effective a 14.5 M4 clone rilfe would be, standard mil spec ? I’ve found a second hand one that’s available and would like to look at this as an option

Posted: 2/19/2007 8:16:20 AM EDT

[#10]

Welocme aboard Loog.

As for the AR's, velocity is your friend.
20" barrels are always best

Mark

Posted: 2/21/2007 9:15:23 PM EDT

[#11]

So for a general plinking range gun with some civilian service rifle I'm looking at something like,

20 inch hbar 1/9 barrel
Right hand side cocking
Flat top upper
A2 Buttstock
Houge type pistolgrip
Free float tube
RRA 2 stage trigger

Few questions,

What sort of muzzle break do people go for ? Whats 'recommended' ?

Is there any particular advantage to an upper with one of those huge risers built in ?

While I don't intend to use a bipod all the time, I'd like the option to use one. Assuming a free float tube of some kind, what the options on attaching a bipod ?

Assuming I want a right hand charging upper - in the UK is there really much in the way of choice for uppers ?

Say I went for something like a Leopold LRT scope - what sort of mounts would be recommended ? Would you need to be able to mount the scope a bit forward of the standard flat top upper rail to get proper eye relief ?

Does the choice of lower make a significant difference ?

Posted: 2/21/2007 10:15:31 PM EDT

[#12]

Quoted:
So for a general plinking range gun with some civilian service rifle I'm looking at something like,

20 inch hbar 1/9 barrel
Right hand side cocking
Flat top upper
A2 Buttstock
Houge type pistolgrip
Free float tube
RRA 2 stage trigger

Few questions,

What sort of muzzle break do people go for ? Whats 'recommended' ?
None, it's not really needed on a service rifle, just stick with the original A2 flash hider just for the looks. If you must have one then the AK style is good, Holland make a good one, there are several to choose from, but you can upset your neighbours on the range and you're strsight in to match rifle class
Is there any particular advantage to an upper with one of those huge risers built in ?
Not really, unless you have a very large scope to stick on top, or you have trouble getting your head down low. It makes fitting iron sights impossible.
While I don't intend to use a bipod all the time, I'd like the option to use one. Assuming a free float tube of some kind, what the options on attaching a bipod ?
You can add a bipod stud very easily, if you go for the military look with the handguards on the float tube you can get the #5 Harris stud for a few pounds (somewhere around £5) or if you have the aluminium float tube a QD stud can be screwed on easily, just drill a hole and either thread it or use a stud and nut.
Assuming I want a right hand charging upper - in the UK is there really much in the way of choice for uppers ?

Say I went for something like a Leopold LRT scope - what sort of mounts would be recommended ? Would you need to be able to mount the scope a bit forward of the standard flat top upper rail to get proper eye relief ?
There are many mounts that will work, just steer clear of the £10 budget mounts, a one piece would be better than a two piece, but I've managed with a two piece for years with no problem. The trouble with the Leupolds is the eye relief - it can be very difficult to get them far enough forward to get proper eye relief, mainly depending on your shooting position. A rail riser that steps forward over the handguards can solve this if it is a problem
Does the choice of lower make a significant difference ?
Again no, if it is a mil spec receiver, and many of the commercially made (machined) ones you can get here are more than good enough. Get a forged receiver if you are going for the standard profile, I have seen one of the cast ones snap when the pins had been too tight, but that could most likely have been prevented if the fit had been better

Personally I don't like the Hogue grip, they feel funny to me as the 'bumps' never seem to be in the right place, so I'd say save your pennies and get more ammo.

Hope this helps

Matt

Posted: 2/23/2007 2:44:28 AM EDT

[#13]

Would a 1/8 or 1/9 twist be the best compromise for shooting 62gr RG and the occasional reload with 69 SMK, and maybe the 77s ?

Posted: 2/23/2007 5:21:05 AM EDT

[#14]

Quoted:
Would a 1/8 or 1/9 twist be the best compromise for shooting 62gr RG and the occasional reload with 69 SMK, and maybe the 77s ?

No point going with a 1:9 when 1:8's are available.
You'll only handicap yourself in the future

Posted: 2/23/2007 6:17:23 AM EDT

[#15]

Quoted:

Quoted:
Would a 1/8 or 1/9 twist be the best compromise for shooting 62gr RG and the occasional reload with 69 SMK, and maybe the 77s ?

No point going with a 1:9 when 1:8's are available.
You'll only handicap yourself in the future

As Mark said.

I regularly receive calls (two or three a week) from people saying they don't want a fast twist barrel as they'll only shoot 55gn, and surplus on the range, and the "the fast twist won't take the lighter bullets". Well if you're possibly gonna shoot the 40gn and lighter bullets at stupid speeds then you might have trouble with the bullets spinning themselves apart, but you cannot over-stabilise a bullet. The slower twist barrel will do less work on the bullets and thereby reduce wear, but you'll never notice the difference as the life will be extended by only a few rounds, and there are other factors that will have a bigger impact on the barrel's life.

You should go for the faster twist if you can, and certainly never go slower than a 1:9".

Matt

Posted: 2/23/2007 7:30:15 AM EDT

[#16]

Quoted:

Quoted:
Would a 1/8 or 1/9 twist be the best compromise for shooting 62gr RG and the occasional reload with 69 SMK, and maybe the 77s ?

No point going with a 1:9 when 1:8's are available.
You'll only handicap yourself in the future

As Mark said.

I regularly receive calls (two or three a week) from people saying they don't want a fast twist barrel as they'll only shoot 55gn, and surplus on the range, and the "the fast twist won't take the lighter bullets". Well if you're possibly gonna shoot the 40gn and lighter bullets at stupid speeds then you might have trouble with the bullets spinning themselves apart, but you cannot over-stabilise a bullet. The slower twist barrel will do less work on the bullets and thereby reduce wear, but you'll never notice the difference as the life will be extended by only a few rounds, and there are other factors that will have a bigger impact on the barrel's life.

You should go for the faster twist if you can, and certainly never go slower than a 1:9".

Matt

I read not too long ago and via a link somewhere on this forum that if a bullet spins too fast it will fly 'nose high' and suffer more induced drag thereby affecting velocity and hence accuracy. Is this not so?

Posted: 2/23/2007 8:54:56 AM EDT

[#17]

Quoted:
I read not too long ago and via a link somewhere on this forum that if a bullet spins too fast it will fly 'nose high' and suffer more induced drag thereby affecting velocity and hence accuracy. Is this not so?

That's just kind of theory that's never been proven, and then it is related only to extended and extreme distances.
For normal shooting is doesn't matter, and besides, even with fast twist barrels and long distances, the bullet holes are still round.

I've never seen a bullet come apart either with lightweight bullets and fast twists.
Bullets are tough little buggers

Posted: 2/23/2007 8:55:10 AM EDT

[#18]

Have you visited arfcom's ammo oracle?

everything you wanted to know and stuff you never thought of

Matt is right (of course) go for 1:8,

ammo oracle explains what twist rates / bullet weights / accuracy distances work best

Posted: 2/23/2007 8:58:24 AM EDT

[#19]

Quoted:
Have you visited arfcom's ammo oracle?

everything you wanted to know and stuff you never thought of

Matt is right (of course) go for 1:8,

ammo oracle explains what twist rates / bullet weights / accuracy distances work best

The ammo oracle is useless. Don't go there

Posted: 2/23/2007 9:13:21 AM EDT

[#20]

Quoted:

Quoted:
Have you visited arfcom's ammo oracle?

everything you wanted to know and stuff you never thought of

Matt is right (of course) go for 1:8,

ammo oracle explains what twist rates / bullet weights / accuracy distances work best

The ammo oracle is useless. Don't go there

Well that's helpful!

So what are you saying Mark. Is it actually best to just work up whatever bullets and loads suit your particular setup by trial?

Posted: 2/23/2007 10:11:29 AM EDT

[#21]

Quoted:

Quoted:
Have you visited arfcom's ammo oracle?

everything you wanted to know and stuff you never thought of

Matt is right (of course) go for 1:8,

ammo oracle explains what twist rates / bullet weights / accuracy distances work best

The ammo oracle is useless. Don't go there

Well that's helpful!

So what are you saying Mark. Is it actually best to just work up whatever bullets and loads suit your particular setup by trial?

The Ammo Oracle has nothing relevant to reloading or manufacturing top quality home made ammo.

If you want to know about wounding and terminal performance, who makes the best M193 or the difference between 5.56 & .223, then it might be useful.

If you want to know about making good ammo, visit the reloading and (dirty word coming up) competition forum.

Shoot competitively and talk to other competitive shooters.

When talking .223 match ammo, it really is simple: Ranges involved = bullet selection.
There are loads of people shooting competitively worldwide and they all learn from each other and everything comes down to a few recipe's.

Bullets:
Sierra, Hornady, Berger, Nosler and JLK. Those will cover everything.
Brass:
Winchester, Remington, Lapua and Lake City.
Primers:
Remington, CCI, Federal, and Winchester. Magtech are OK and I've heard that PMC (Russian) are very good.
Powder:
Hodgson, Alliant, Accurate Arms, Ramshot, IMR.

Look at what everyone else shoots, they can't be wrong, and there's absolutely no point in diversifying or detouring from those tried and tested loads because they've already been tried and discounted.

Proven loads:
52gn Matchkings and H335 or W748
69gn Matchkings and Varget, W748, H335, Reloder 15, N140, AA2460
77gn Matchkings and Varget, Reloder 15, N140 & 540, AA2520.

There's other concoctions but these will get you going.

Before starting to reload, please post here for further detailed info.
There's plenty of advice to be had from our board members

Mark

Posted: 2/24/2007 12:11:42 AM EDT

[#22]

Quoted:

I've never seen a bullet come apart either with lightweight bullets and fast twists.
Bullets are tough little buggers

I've shot 52gn Sierra MKs out of a 1:8" but never checked the speed - I only had a box lying around and 100yd range, no need to chrono. No problems at all.

I think the bullet coming apart is becoming a bit of an urban myth, the best kind - one that sounds like it could be true. Nobody I know has actually mentioned they've seen it happen, I've never seen it happen, and neither has Mark and between us we've seen plenty of 'close to the edge of the envelope rounds' as well as hundreds of thousands of normal reloads go down range, but many will still believe it and make pretty big decisions based on the 'fact'.

Matt

[ARCHIVED THREAD] - Straight Pull AR15 Spec

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