AR-15 A2?

[swt5]

A very good deal on some .223 55gr PSP's prompted me to drag a 30+ year old AR-15 out of the safe and have a go with the ol' gal at 50 yards. I was pleasantly surprised to keep a 20 round mag inside of 1.5" using the OEM aperature sights and my failing eyesight. I thought I would try scoping it to see how tight I could get her so I mounted a Bushnell 6500 2.5-16 42mm to the carry handle using the usual channeled picatinny rail that attaches via a single bolt. At the same distance, I could only keep 20 rounds inside of 1.75" and my best was to equal the iron sights at 1.5"? The scope is tried and true so my attention turned to the fact all the weight of that glass is sitting way above the barrel axis being held in place by only that one bolt? I've heard some are applying release agent to the carry handle channel and glass bedding the picatinny base before cinching up that bolt and this helps secure things a bit.
My AR is the A2(?) variant with the triangular handguards and standard barrel. Is there a better designed carry handle mount out there or am I just trying to make a silk purse out of a sow's ear? I want to keep the rifle OEM and am starting to think it may just be resigned to a life of a 50 yard iron sight plinker? Feedback appreciated...

 

[jonbearman]

What load are you using and what brand of bullets are you using.You should be able to do better than that even with the light weight sp-1 barrels.Give us some details.I wouldnt be shooting the original trigger as they are hard on accuracy.You can save your original parts and get a timney or chip mc cormick drop in trigger.This will change the whole ball game.

 

[nhm16]

Just about every carry handle scope mount will wriggle or rotate slightly so that you will never get a rock solid scope installation. What you can also do (besides trying the bedding) is to secure the mount to the carry handle with another screw, but then you have to drill into your AR.

 

[swt5]

What load are you using...I wouldnt be shooting the original trigger as they are hard on accuracy.

Factory Winchester Ranger. I know I could cook up a recipe that would shoot better but I have other rifles and loads if I want to be more precise. My purpose in this instance was to take advantage of several dozen cases of ammo that could be had at a very low price. Yes, the factory trigger is a nightmare! Unfortunately, Homeland Security laws will not allow a drop in trigger to be shipped up to Canada I may look into a trigger kit on my next visit down...

Just about every carry handle scope mount will wriggle or rotate slightly so that you will never get a rock solid scope installation. What you can also do (besides trying the bedding) is to secure the mount to the carry handle with another screw, but then you have to drill into your AR.

Agreed. It's apparent the design didn't take into account the requirement for a solid platform on which to mount higher magnification optics. I may be able to live with a second hole in the handle though...
Thanks Gents.

 

[Beau]

I'd try bedding it first. And put some pipe insulation on the stock to give you a higher comb for better cheek weld.

When you have the weight of a scope up yonder, you have to watch out for canting too.

 

[pdhntr]

Years ago I only had the A-2 and with eyes going, I had to scope it. I very likely used the same mount you used. And the same thing happened.

I started out glassing in the base, but after some time it was loose again. I finally realized the sides of the base would gradually squeeze in and loosen up.

So I worked down some aluminum to fit in the channel to reinforce the sides. I glassed them in place and retightened the screw. Problem solved.

Oh.......... and wrap a piece of leather around the base screw and tighten with a pliers. Finger tight won't make it.

Jim

 

[Minesweeper3433]

If it is just plinking why worry about putting the scope on it? If you wanted to mount the scope why not just get and A3 or even better just the upper receiver and swap out the one part.

 

[ar15topgun]

I'm gonna say it has more to do with cheek weld and not being able to repeat the same hold on each shot. With the iron sights one can do fairly well with repeating stock weld but with the scope that high up it's impossible unless you put something on the stock to compensate for the additional height.

 

[markm87]

I'm gonna say it has more to do with cheek weld and not being able to repeat the same hold on each shot. With the iron sights one can do fairly well with repeating stock weld but with the scope that high up it's impossible unless you put something on the stock to compensate for the additional height.

Very true... that scope is probably paralaxing like crazy... even at 50.

Carry handle mounting an optic is just sub optimal no matter how good the scope.

Shoot! With those irons, you should be trying to ring the gongs at 300-500 yards.

 

[hogan]

Triangular handguards? Sounds like an original SP1 model unless the rear sight has windage and elevation adjustments. A1 rear sight has no elevation, front sight controls the elevation. Probably a 1:12 Twist. I dunno if the handguard sight channel is same dimension on A2 as A1.

If want to use a scope need a mount and rings that keep scope as low as possible. Leupold VX-II 1-4 is most compact I've seen. Ocular lens is smallest diameter and most compact oal which helps greatly. Smith Entps ch mount is best I've used. Can mount the Hensoldt 4x H-K 91 scope on this base and it makes a pretty decent fast reaction scope being even shorter and lesser diameter than the Leupold. Haaku made some blue-line scopes with carryhandle mount that are supposed to be decent. I had a Colt scope for a while and didn't like it as much as the Hensoldt.

Your AR-15 SP-1 A1 might be collectible. A really nice rig for accuracy buffs is a flat-top Service Rifle, like from RRA. You get detachable match iron sights and can mount scope as you wish. Remove the hidden float tube and handguards and go with an aftermarket like a JP Entps or Badger Ord and you have a real tackdriver that is also cool. Shoot them 80gr match bullets to 600yds or more with fine result. Upgrade to a Giesele trigger and you are about done...

 

[swt5]

...that scope is probably paralaxing like crazy... even at 50.

The scope is SF and parallax was dialed out of it and checked at 50. I shot it off of sand bags using my left hand as a cheekrest and the scope has an anti-cant bubble so I'm quite confident parallax and canting are not issues here.

Triangular handguards? Sounds like an original SP1 model...
Your AR-15 SP-1 A1 might be collectible.

You are correct hogan, it is an SP1 model and the serial number puts the date of manufacture at 1979. Don't know how collectible that makes it? Are you referring to the small or large FCG pins issue?
In any event, I'll be installing an A.R.M.S. #39 mount on it. Hopefully the second attachment point at the front of the handle will secure it better. I also plan on getting a Delta cheekpiece. Hopefully these will improve shootability a bit...

 

[swt5]

I received and installed the A.R.M.S. #39 mount today. I could tell immediately this thing was going to hold rock solid! Using the same ammo/scope combo at 50 yards I've shrunk my 10 shot groups from 1.75" down to .75"! With a proper front rest and cheekpiece I should be able to shave another .25" which is perfect for my needs. The A.R.M.S. mount cost 4 times as much as what I had but this is definitely a case of getting what you pay for!
Thanks for all the suggestions.

 

[markm87]

Cool. Post a pic of the final set up if you get a chance.