Lee 55gr Cast Boolit Loads in AR-15?

[FLHTC]

I use 18 grains of AA2200 with an RCBS 22-55. Cycles fine and groups into 3.5" at 100 yards. Nothing to write home about but cheap plinking. I wouldn't hesitate to use it on Varmints.

[Motor]

The question in post #15 was can Unique run an AR.
The answer is no. This has nothing to do with your response.
Does Unique impart the correct RPMs or is that not a consideration?

Is this a real post or some kind of tongue in cheek joke?

Exactly how does a gun powder "impart RPMs"????

RPM's are a result of velocity and twist rate. It doesn't matter what powder you use.

Plus I'd be willing to bet that a "AR" with a pistol length gas system and the correct chambering (that's caliber if you're a little slow) can be persuaded to run on Unique.

Motor

[Motor]

I have been using min jacket data w PC coated bullets.

Tackleberry. Is that with or without gas check? Can you offer any specific loads. You can PM them if you want.

Motor

[Harter66]

Motor
Jmorts post was a cheap reference to the over stabilized accuracy failure that can result from a twist to fast for length of bullet and velocity .

My research has given me a number 13-18,000 psi at the gas port for proper action function of the AR15 action . That can be altered some with buffers and springing and maybe even the bolt carriers . I doubt that an accurate Unique load would cycle reliably in short of a purpose complete SBR or pistol .

[jmort]

"Plus I'd be willing to bet that a "AR" with a pistol length gas system and the correct chambering (that's caliber if you're a little slow) can be persuaded to run on Unique."

It it would be nice to run an AR on Unique. I remain a doubter, but would love to be wrong. Hopefully, in the fullness of time it will be possible.

[Motor]

Guys. What diameter boolit size die do you recommend for this project? I have a .224" but don't think it's large enough. I have the means to lap it larger but to what size?

Motor

[FLHTC]

I use 224 with 10% Linotype and carnuba red. Aluminum or copper checks. With my bolt oiled well, they feed flawlessly and as fast as I can pull the trigger

[Motor]

I opened it up to about .2255" Gonna load some test rounds this evening.

Motor

[FLHTC]

Make sure the neck of the finished round is not too wide otherwise you will have chambering issues

[Motor]

Make sure the neck of the finished round is not too wide otherwise you will have chambering issues

Ok. I'll make a "dummy round" to test fit with and chamber/extract it by hand. I'll paint the neck up with magic marker too.

Motor

[FLHTC]

And oil your bolt well also. When I started making cast rounds for my AR, i had ejection issues and thought it was the load itself. A jacketed factory load often has enough pressure to cycle a dry bolt. Not so with cast loads. It helps tremendously to have the bolt generously oiled when working with cast AR loads. The wives tale about clogging your gas ports with lead is just that. The pressure needed to blow the bolt back will certainly blow the barrel gas ports clear. Have fun

[Motor]

Ok. I'll run her wet with CLP. It's a new upper too so running wet was never a question.

I'll be using powder coated bullets with aluminum gas checks. I was going to go without the checks and I will still test some without but my brother bought a thousand of them so I figure why not......

Motor

[Motor]

I tried 15 and 16gr RL-7. Both ran the rifle with it well lubed with CLP. Groups at 50 yards were about 4.5"

Then I tried 18 and 19gr of H-4895. The 18gr load shot well enough for me to keep working. 8 of 10 are in a group less than 2" which is smaller than the red dot optic being used.

This was with gas check. Without the gas checks the groups are about 2 feet. There is no evidence of bullet or PC failure they just simply don't shoot accurately.

Motor

[Motor]

I've already tried with/without GC. You're going to need it for accuracy. Without it, I couldn't hold minute of berm.

You and Tackleberry are absolutely correct.

The gas check makes up at least half of the bearing surface on this boolit. I can easily see why this design needs it for stability.

Thanks for the great feedback.

Motor

[Smk SHoe]

Kinda on the same topic, I finally got the Arsenal .223 "Elvis" running in a AR. It's a slick side and about 62ish grains. Loaded to mag length and 21.0 grains of 2230 and runs like a dream. I had problems with the lee 55, to short of a bullet to want to load reliably from the magazine. Some have done it, I wasn't gonna spend the time messing with it. Also the "Elvis" has a lot of bearing surface.

[Motor]

I didn't have any trouble with feeding. I hate to modify the 6 cavity mould for an experiment but have to think if the gas check bore was moved making it a .225" flat base bullet that it would work just fine.

I may buy a 2 cavity and try it.

Motor

[jukeksi]

I had problem 20" 1:8 twist ar15 all test group was 20" to 1 feet. Whit cast 62gr pc bullet.
Thos gc is reguired on 223?

[WickedColt]

I had problem 20" 1:8 twist ar15 all test group was 20" to 1 feet. Whit cast 62gr pc bullet.
Thos gc is reguired on 223?

It seems like gas checks help this caliber because it stabilizes the base (I could be wrong as I am newer to this but that's what I got from reading up on it).

[Motor]

It seems like gas checks help this caliber because it stabilizes the base (I could be wrong as I am newer to this but that's what I got from reading up on it).

Exactly. If you look at the Lee 55gr RF without the gas check it only has a narrow band in the middle of the body. Everything fore and aft makes little or no contact with the bore.

I have some time to think over options. I have a thousand checks to use up.

Motor

[JonB_in_Glencoe]

It seems like gas checks help this caliber because it stabilizes the base (I could be wrong as I am newer to this but that's what I got from reading up on it).

You are on the right track. The GC does a few things. One of the biggest things is:
A imperfect base on a cast boolit will effect accuracy as the boolit leaves the muzzle, much like a imperfect crown on the barrel.
while not nearly as important for pistol type shooting...Rifle shooting generally demands much more accuracy, So little things add up.

Also the "Gas Check", does as the name implies, it will better seal the bore as the boolit is launched than a boolit without a gas check...Again, with Rifles, which typically have higher pressures, a GC is more required than pistol loads.

A GC does some other magic too, so much so, that we don't even know?