Heavy bullets in an AR-15 Carbine 1:7

Airborn_69

Airborn_69

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OK, I've been shooting stock ammo for a while & all seem to fire good out of of my 14.5 w/ 1:7 twist upper. I plan to reload full time now that .223 ammo is out to lunch in prices.

I have tried with succes:

1) 77gr BTHP's (Black Hills),
2) 75gr BTHP's (Hornady)
3) 69gr BTHP's (Fed GMM) which scored to lowest out of the 3.

Only concern with this is I have a RCO M4 ACOG which might need a little adjustment since it is zeroed & calibrated for 62gr FMJ's.

Any concerns I'll listen & am assuming the powder used for most of the above would be Hodgdon Varget right??

I'll also listen to any secret recipes :eek:
 
Airborn_69 said:
Anybody know which reloading set-up would be good for semi auto fired .223?
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Progressive, I have a dillon xl650 that's served me well, though if I'm doing varget/rl15 I'll still weigh the powder with a chargemaster.
Only concern with this is I have a RCO M4 ACOG which might need a little adjustment since it is zeroed & calibrated for 62gr FMJ's.
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I used this same setup for service rifle last year. With 69's, the BDC was close enough (my poor shooting was a bigger concern) ;). However, some guy on arfcom did a whole bunch of calculations for offsets with different ammo/barrel lengths, so you may want to have a look:
http://www.ar15.com/forums/topic.html?b=3&f=18&t=229420
 
Not competing, but trying to wring out max accuracy indoor at 50 yards last winter with 1/7 16" Stag nato chamber and 1.5-5x30 Menace and Larue mount, carbine gas, no FF, shot off bags.

Before I got the scope setup, I'd tried to approach MK262Mod1 based on its quoted performance of 2669 fps from a 16" 1/7 and 77gn SMK.

With fresh cut Win brass, Fed205 sr, 24.5 gn Varget and 75gn Hornady BTHP I got 2667 fps ave. Sd's were 17-18. The primers looked okay, but there was some occasional stickyness and slight tearing on the brass rims. Real clean compared to plinking load as follows:

24.5 gn WC-735 55gn Hornady bulk sp. (ave 3017 fps and duplicates Win USA V's outa my gun). Smells great but dirty. (My range requires soft points, and yeah, both those loads happen to be 24.5 gn).

Once I got the scope setup, I couldn't get better than 3/4" groups of 5 at 50 yards with either load. I tried tweeking the 75BTHP/Varget load down to 23.7 gn incrementally with no joy. Expensive bullets and stick powder that my Dillon 550 measure needs finessing (a good whack) for 1.5 MOA? Not at those prices.

I'd heard Benchmark might meter better and google got me to this SniperCentral post:
http://www.snipercentral.com/forums...&start=0&sid=5ac906ac14eff8f254f18972ab732e45

Fast forward, and the load outa my gun is with 60 gn Hornady Spire points over 24.5 gn Benchmark wsr win brass. 1/4" to 1/2" inch at 50 yards all day long (2865 fps), no stickiness, no brass tearing, very clean, and meters great (smaller sticks than Varget). The 60's would suit your ACOG BDC (?) better I suppose.

And yeah, I know all the High Power guys are doing Varget and heavies, but they're all using 20" - 24" barrels with rifle gas systems. I have some serious reservations about such loads and shorties. YMMV.

If you're a volume shooter and your time is worth something, the Giraud trimmer would be the way to go. I'm not a volume shooter and money's tight now, so I do the Lee hand tools with powered screwdriver, and that SUCKS!

A typical Dillon 550 setup (popular with US 3-gunners) is with an extra toolhead ($20 ish ?) and just put a single size/decap die in it. Lube and run all your brass through, tumble off the lube, then cut chamfer/deburr. Next put in the toolhead with the set of 223 dies in (put a universal decap die in the first position to knock out the tumbling media from the flash hole). No need to crimp.
 
Well I did it, went to the beautiful range we have here in Grande Cache (15km+ north of town.) and actually fired a whole variety of ammo out of my 1:7 14.5'' AR w/ACOG.

Bare in mind that it was a bit windy, was in a valley with an altitude of about 1000m, temp +9 degrees C. The results are not 3 round MOA but rather 5 rd approximate groups.

- Swiss RUAG 63gr FMJ 1) 1.5-1.75'' 2) 1.25-1.5''
- Hornady TAP 75gr BTHP/WC T2 1) 1.5-2'' 2) 1.75-2"
- Black Hills 77gr HP 1) 1.25-1.5'' 2) 1-1.25''
- Federal Goldmedal 69gr BTHP 1) 1.5-2'' 2) 2-2.25''
- IVI 62gr FMJ 1) 2.5'' 2) 2.5''
- AE 62gr FMJ 1) 2.5'' 2) 3''

All shots were from a bench supported by a sandbag.
 
outnumbered, you may want to try your same experiment at 100-200meters. I've found that in a couple ARs I've had, the heavy bullets don't shoot very well up close, and need 100m+ to settle down.
 
The Hornady 68 gr has a heavier jacket than the Sierra 69. In some Ar's that is an advantage.

The Hornady 75 gr hollow point match should work very well at longer range. If you plan on shooting beyond 100 yards, the lower wind drift of the 75 would be an advanatge.

varget should work well with both weights.
 
BC_Guy said:
outnumbered, you may want to try your same experiment at 100-200meters. I've found that in a couple ARs I've had, the heavy bullets don't shoot very well up close, and need 100m+ to settle down.
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Yeah, I've heard that a lot also. Unfortunately it's an extra 3/4 tank of gas round trip to get to my 200 yard range, and I already shot off the remaining 75gn BTHP's and Varget I had. I hear the 60gn SP's are supposed to be very nice inside of 200 yards though. I should have a chance to get out there after the election insanity is over.
 
Before I got the scope setup, I'd tried to approach MK262Mod1 based on its quoted performance of 2669 fps from a 16" 1/7 and 77gn SMK.
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wish I could get Black Hills secret recipe for the 77's :)

Just clowning around that same I did fire some at 200m and both the Black Hills & Swiss stuff went well. I didn't mesure up the group but noticed they were all where they should have been.

Ran out of TAP 75's so I didn't try them out.
 
wish I could get Black Hills secret recipe for the 77's
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The bottom of the first post in this thread has some BH specific data from a Guns&Ammo mag test of Mk 262 Mod 1. The whole thread is storehouse of related info and user data:
http://www.calguns.net/calgunforum/showthread.php?t=54716

I'm just not thrilled by how my gun operates with such loads; I'm thinking it might be displaying the shortcomings of a mid-length barrel and carbine gas system, a problem you wouldn't have. I got a lot of case heads with ejector burrs. No more with the 60's and Benchmark.
 
MK 262 is a hot load. If I was using them operationally, I would want them that way. If you are punching paper you can afford to back them off a grain and deal with the resultant extra elevation you need at distance.
My load is 24 grains of Varget under the 77SMKs
 
My old service load was:

- 69gr SMK
- 26gr Varget
- CCI 400
- Winchester brass
- 2928fps

My new load is:

- 77gr SMK
- 24.5gr Varget
- CCI 400
- Winchester brass
- 2812fps

The 77gr load groups a bit better and bucks the wind better, it also shows less pressure. The 69gr load is a bit warm and I needed to put an M16 carrier and heavy duty buffer spring in the rifle to tame it down a bit by slowing the unlocking of the bolt.

Edited to add that this is 223rem and the rifle is a 1:7" 20" AR15. The 77gr load also works well in my BlueStar but it has been rebarrel from the stock 1:10" to 1:7" twist.
 
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