Designated cast AR15

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  • Last Post 11 May 2019
shastaboat posted this 23 July 2018

When I last attempted to get my AR,16", 1 in 9" twist AR to shoot and cycle with 55 gr LEE over 10 gr of 2400 I could not get it to cycle even with a cut down recoil spring and a lightened buffer.  I'm planning to build a designated AR15 for this cast load only.  I want to use a 20" 1 IN 12" twist; preferably non-chrome lined barrel.  I've found Green Mountain Barrels sells a 1 in 12" chrome line barrel but I prefer a regular steel barrel and not even stainless steel.  Does anyone know of a source of original 20", 1 in 12" twist new M-16 barrels.

Also I would like info on what length gas system would work better on this project; if a reduced poundage recoil spring and buffer are available and what size gas port is needed.  I understand if I use an adjustable gas port that I may be able to also shoot standard jacketed 55 gr rounds but that is a secondary need and would not be pursued if not readily possible using 10 gr of 2400 and 55 gr cast bullets.  Thanks in advance for any suggestions.  

Because I said so!

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shastaboat posted this 11 May 2019

The whole point about this post was to build an AR15 platform rifle that I can shoot the same cast ammo in that I use in my bolt guns.  Most of us know the limitations of velocity, alloy, lube and powders that consistently provide good to excellent results in cast bullet shooting.  Also the individuals who actually have experience with AR platform rifles and other semi auto rifles know the difficulty of shooting cast in a semi auto to insure functionality and accuracy.  Unique to an AR platform is the breaching and bolt system with a multi lug rotating bolt face and corresponding breech face.  In addition this build will shoot jacketed full power ammo if two buffer parts are changed.  So I promise on my deathbed to convert this weapon to shoot full power ammo before I die.  As my 32 year old son is my sole beneficiary of my trust/estate and is aware of the many wildcat rifles as well as specialty arms and is quite aware of AR platform rifle designs and including this special build, I think I am safe in believing that no ill results will ever come of this "DESIGNATED CAST AR15".  Maybe I should just paint the muzzle "Pink".

Because I said so!

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M3 Mitch posted this 11 May 2019

I'm not in habit of leaving my weapons around where just anyone can get a hold of them.  And I can shoot jacketed mil spec or commercial ammo in this by installing a standard rifle spring and buffer and adjusting the gas block to a more closed position.

 

I don't leave my weapons around or loan them out either, but, keep in mind they "outlive" us.  Just sayin'.  Not a big deal, but the general principle started I think with the .357 Magnum, to do something with the "hot" ammo so it won't get into gats that are not appropriate for it.

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shastaboat posted this 08 May 2019

I'm not in habit of leaving my weapons around where just anyone can get a hold of them.  And I can shoot jacketed mil spec or commercial ammo in this by installing a standard rifle spring and buffer and adjusting the gas block to a more closed position.

Because I said so!

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M3 Mitch posted this 08 May 2019

I'm a bit late posting this, but, it might have been a good idea to have built this upper on a slightly shortened, or at least with the shoulder set back, case, to preclude anyone putting military ball ammo in it while it's set up for cast only.  Just a thought.  More for anyone else who might decide to give this a try. 

It's always great to read on here where people are doing stuff that the unwashed majority would have said can't be done!

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shastaboat posted this 08 May 2019

Not sure why my post from yesterday posted in two spots.

Because I said so!

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shastaboat posted this 07 May 2019

April 2019 update! 

So I took this "Designated Cast Bullet AR15" to shoot squirrels a couple of weeks ago.  I had already turned the barrel down to .600" straight contour in front of the .750" gas port to the muzzle and re-parkerized it.  I had not replaced the round floating forearm since building the rifle and also had the carbine adjustable stock on it.  I wasn't happy with feel of the rifle and frankly the round floating forearm wasn't very stable so I ended up shooting my Browning A-bolt the entire week of squirrel shooting. 

I ended up shooting about 1200 rounds for the week and figure about 50% hits out to 300+ yards.  100% at 50; 80% at 100; 50% at 150-200; and about 20% at over 200 yards.  Average was about 50%.  This gives me a kill rate at about 600 squirrels in 5 days of shooting.  2 days were raining and overcast...no squirrels to speak of...

When I got home I ordered and A1A2 solid stock and a streamlined light weight forearm with a flat base that is only 1.5" diameter. (removed the 2.0" round one...it's for sale).  Because the A1/A2 stock tube is longer than the carbine length stock tube I decided to use an stock carbine length spring and the weightless carbine buffer I used before.  They worked flawlessly with 100% reliability, extraction and bolt hold open on the last round.  The lightweight streamlined gas port is adjusted fully open without enlarging the gas hole in the custom pistol ported 7.5" ported, 20" McGowan bbl.

Today, I went out to my BLM private range to test and sight in a bit more.  Wind was gusting at 12-15 mph from about 1:00 o'clock.  Not prime shooting!  I'm extremely excited about the potential of the rifle now.  I will post a pic of the rifle and 2 targets I shot today.  50 yards and 100 yards.  Not stellar because of the wind but the potential is there.  The rifle is much more stable and comfortable now.  I do see me shooting more rounds than my bolt guns with reloads after 20-30 rounds instead of every 4 rounds or between each shot.

I'll be using this AR when I go back on my next squirrel shoot in late June after the first alfalfa cutting/baling.  I figure to clean the carbon fouling after every 100 rounds or as needed when accuracy falls off.  That's what I do with my bolt rifles.  No leading in any of them. 

Now to get back to casting, sizing/lubing, brass prep and loading.  Thank God I'm using a LEE Pro1000.

Because I said so!

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shastaboat posted this 18 September 2018

I wouldn't know where to start.  I have communicated with an individual in Gardnerville, NV that shoots with the Modesto CA club that I will contact to see if he would be able to coach me through the process.  I know he shoots in the desert down there too.  It's about 1.5 hrs drive.  Another thing I'll do sometime this week on a windless day is to go out and set up on my BLM range and take some pics.  I have target stand bases set in concrete at 25, 50 and 100 yards.  I'll take a pic of my best target and post it here.

Because I said so!

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John Alexander posted this 18 September 2018

I know our matches are few and far between in many parts of the country.  You might try a few postal matches to show the flag for the AR folks.

John

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shastaboat posted this 17 September 2018

You mention that you might be interested in competing in a match. I am sure that any CBA match there would be shooters to help you out and I encourage you to give it a try with either your ARs or bolt guns.

There are two classes for factory rifles and two for custom rifles and with the accuracy you cite in your above post you would have probably  won in any of them at the CBA nationals just finished a week ago. 

I think it would be good for CBA shooters to see that an AR can compete and it might encourage others to give them a try.

John

 

John,

If you can encourage any Cast Bullet Assc competitor in the Reno, NV area to contact me and we'll see if my participation is possible.  I know that they have a few shoots in Nevada.  The nearest sanctioned range from me is almost 2 hours away by paved road and only an hour by dirt road.  I think the Spring shoot is either in Winnemucca or Elko, Nevada which is quite a distance.  We'll see.  Thanks, Brent

Because I said so!

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John Alexander posted this 17 September 2018

You mention that you might be interested in competing in a match. I am sure that any CBA match there would be shooters to help you out and I encourage you to give it a try with either your ARs or bolt guns.

There are two classes for factory rifles and two for custom rifles and with the accuracy you cite in your above post you would have probably  won in any of them at the CBA nationals just finished a week ago. 

I think it would be good for CBA shooters to see that an AR can compete and it might encourage others to give them a try.

John

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shastaboat posted this 16 September 2018

I'm shooting the Lee C225-55-RF bullets, Sage aluminum checs, cast in straight WW, sized .225 and lubed with my 50% beeswax/50% Lithium based hi speed wheel bearing grease to 2000 fps.  Both my bolt guns will shoot to less than 1/2" at 100 yards if I am very critical with casting, culling, weighing. etc...If I'm not as critical with them and cast and load for volume then my groups expand to 1" at 100 yards.  So far I've been able to equal the accuracy with the AR.  All three are 1 in 12" twist.  The other day I was shooting in a 15 mph cross wind and accuracy spread out to 3-4 inches with a horizontal spread.  Go figure!...lol...

My cast shooting is aimed at shooting either for pests, varmints or game.  I've never competed in a match but might if I had someone to coach me through the process just for fun.

I really think going heavy may not be the way to go in .223/5.56.  By going heavy you then may require a faster twist barrel and consequently may have to reduce velocity under 2000 fps.  I started shooting cast in .223/5.56 when 22RF ammo went out of site cost wise.  My cost per cast .226/5.56 round is under 7 cents per round.  I would say my cast rounds pretty much exceed what you can do with a .22K Hornet.

I may someday cast some harder bullets and alloy them with 10% linotype.  If I was match shooting this may be the way to go and boost velocities to 2400 fps.  However in my past experience I've always attained the best accuracy at around 2000 fps except for that 6.5x55 fast twist military barrel.  I built a 6.5x55AI with a 1 in 9" twist that may be accurate up to 2000 fps.  Just never shot cast in it yet.  If I do I'll use the 266455 bullet.

Because I said so!

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358156hp posted this 16 September 2018

I'm accumulating a 225 mould and tooling (Star Die) for a similar project. After reading Ed Harris' article on cast in the 223 I decided to pursue a more beaten path, and have ordered a 62 gr NOE mould, and of course a .225 sizing die for my Star. I could have gone heavier on bullet weight, but my slowest twist barrel is a 1-10, and that may not even see cast. My carbine barrels are 1-9, and this should work out fine until my goals end up better defined. I will use conventional lubing for this project, at least to start out with, I have some lingering misgivings about powdercoating such small, lightweight bullets.

http://www.hensleygibbs.com/edharris/articles/Cast%20In%20an%20AR.htmhttp://www.hensleygibbs.com/edharris/articles/Cast%20In%20an%20AR.htm

http://noebulletmolds.com/NV/product_info.php?cPath=24_110&products_id=361

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John Alexander posted this 16 September 2018

Shastaboat,

I was never able to get them to stabilize in a 12" twist and know other that couldn't.  Maybe some have at higher velocity.

I don't know at what velocity they can be driven with practical accuracy.  Accuracy always fell off for me well before 2,000 so I quit.  Depends on what level of accuracy you are satisfied with.

John

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shastaboat posted this 16 September 2018

Just as a point of information the the 70 grain NOE bullet will stabilize in 1 in 10.5" or quicker twist -- from actual experience.

John

 

Does that mean a 1 in 12" twist will not stabilize them?  Also at what velocity can they be driven in a 1 in 9" or 1 in 8" barrel for accuracy?

Because I said so!

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Scearcy posted this 15 September 2018

Shastaboat

Probably just punching paper which might include some of our local CBA matches. We do shoot 200 yards in these matches so the extra weight helps a little. Mostly I would just like to get an AR going with cast for my own education.

Jim

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John Alexander posted this 15 September 2018

Just as a point of information the the 70 grain NOE bullet will stabilize in 1 in 10.5" or quicker twist -- from actual experience.

John

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shastaboat posted this 15 September 2018

Jim, If the 70 gr bullets will stabilize and shoot accurately in a 1 in 9" twist barrel, I am sure that a carbine length system can be made to work with the appropriate powders.  That said, Green Mountain Barrels makes carbine length barrels in 1 in 7"; 1 in 8"; and I think 1 in 9".  All of these same twist barrels are available from other sources as well at less cost than Green Mountain.  My 1 in 9" barrel is quite accurate with 55 gr jacketed bullets at full power.  Others have used the 69 gr jacketed bullets with good results in a 1 in 9" barrel.  I have another low cost build, total $310.00 cost build including the lower receiver with 1 in 8" that would be fine with heavy jacketed bullets.  The trend for builds with 1 in 7" twist for heavier than 70 gr bullets is foolish to me.  Maybe they would be a good hog gun.  I really don't know.  I would be glad to test try some 70 gr cast bullets in the 1 in 9" upper to see how they perform.  Are you just wanting to shoot targets or what?  My experience with fast twist barrels in cast as previously stated in 6.5x55 required me to drop velocity to approx 1700 fps using WW to stableize.  We both know that a drop in velocity equals a drop in pressure.  An AR requires pressure to function.  It becomes counter productive.  We also know that a slower twist with the appropriate weight bullet that will stabilize in that slower twist generally are more accurate with cast bullets.    

Because I said so!

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Scearcy posted this 15 September 2018

Shastaboat

Thank you, I understand. I like the slightly heavier bullet. My hope is to do the build with a non custom barrel if possible. While I have not yet done my homework, perhaps a 9" twist barrel with carbine length gas port will be an easier item to find.  I have a friend with a copy of Quickload. I will get him to do some modeling with different powders.

Your process of working through the issues is very helpful.

Jim

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shastaboat posted this 15 September 2018

I built my Designated cast AR with the pistol porting because I wanted to use my load of 10 gr of 2400 and the Lee Bullet because it shot so well in my bolt guns and did a fine job on ground squirrels and jack rabbits.  I tried that load in a 1 in 9" carbine and it would not cycle so I never bothered to test the accuracy in the Carbine AR.  Both my bolt guns have 1 in 12" twist.  Others have gone a different route.  I succeeded in building an AR that will cycle and shoot as accurate as my bolt guns with the same ammo.

 

Because I said so!

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Scearcy posted this 15 September 2018

Shastaboat

The NOE 70 gr is a flexible and relatively easy to deal with design. I have seen it used in both 9" and 8" twist and it performs well most of the time. It also does not require special consideration in powder choice. The CBA has a very well known member who shoots Titegroup in his 223 as a match load with these and even heavier bullets. My question really concerned the timing of the pressure curve with a heavier projectile.

Jim

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