AR-15 range report [Archive]

z4lunch

03-05-2009, 08:00 AM

Steve here...
I got out to the gun club yesterday...with my ar
Heres the scoup...
1.7/7 twist Krueger
70 grain Oldwest made from ww plus 2% of 95/5 tin antimony and water quenched dropped at 65. Gas checked and 1/2 grain of Poly Fil in each load
I started with 14 grains of Imr 4198 2214fps on my Chrony
16 grains of imr 4198 2544 to 2569fps
18 grains of imr 4198 2754 to 2855fps

Four rounds never hit or made it to the target at 50yds
I don't know if they vaporized or just missed the 8.5X11 target
The action pulled the empty shell all the way out of the chamber but not far enough to eject it.
I would guess the bullets are going way too fast already but I need more gas to function the action
Steve

j20owner

03-05-2009, 10:21 AM

I thought I'd read somewhere that 4198 doesn't create the right pressure curve to operate an AR15. Your velocity with 18 grains is right in there for the bullet weight, though.

rockrat

03-05-2009, 10:22 AM

Slower powder? Something along the lines of H322 or AA2015br maybe to bring port pressure up?

joedapro

03-05-2009, 10:29 AM

i use the rcbs bullet with 8.5 grains of unique. it cycles my colt. my twist is slower though.

z4lunch

03-05-2009, 10:49 AM

Slower powder? Something along the lines of H322 or AA2015br maybe to bring port pressure up?

That was what I was thinking too. But besides needing more gas I think I would want to slow the boolits down too...
Do you think the boolits were coming apart at 2800? Is that to fast, or is the 1.7/7 to much twist
Steve

rvpilot76

03-05-2009, 02:18 PM

Sounds like a combo of both; too fast for the twist.

StarMetal

03-05-2009, 02:26 PM

That was what I was thinking too. But besides needing more gas I think I would want to slow the boolits down too...
Do you think the boolits were coming apart at 2800? Is that to fast, or is the 1.7/7 to much twist
Steve

No, I don't think they are coming apart. I got some 70 grain bullets from Bullshop long ago and they weren't even water dropped. I loaded them with the powder I use for my 55 gr jacketed load and deliberately pushed them over 3000 fps to see if they would not show up on the target at 100 yards. The all did and none of the holes were keyholed. I wasn't shooting for a group, but to see if they would stay on the target. The group was large. The AR is a Colt HBAR with the 7 twist. No leading either.

Now my 6.5 Grendel AR H4198 is THE powder for it. The barrel is a Lothar Walther with an 8 twist and it shoots very well. I love 4198 in that rifle.

Joe

Lloyd Smale

03-05-2009, 08:16 PM

my guess is your twist is going to be to fast for cast work.

z4lunch

03-05-2009, 10:31 PM

rvpilot76

03-05-2009, 11:41 PM

Keep the mold, the new 12 twist will stabilize it. I'd also move to a slower burn rate powder, as previously suggested.

Kevin

rockrat

03-06-2009, 10:51 AM

If you decide to get rid of your mould, let me know, as last week I put an order in with Bernie for one of these moulds. I could cancel the order or have him make me something else.

Gee_Wizz01

03-06-2009, 03:18 PM

z4lunch

03-08-2009, 12:51 AM

Dont give up that easy. Try some different powders and maybe slow it down a little. I think you are stripping the rifling and the bullet is tumbling right out of the bore. Have you slugged the bore? Your bullet diameter may be a little to small.

G

I plan on running some 225450 Lymans down my 1/12 twist HK 93, If I get anything positive from that i will probably get a Krieger 1/12 for my AR

revolver junkie

03-08-2009, 04:17 AM

ill 2nd the slower powder route hopefully you can find a slower powder with a lower load density that could solve at least 2 problems but may also let the bullet accela little slower wich may help?
RJ

DAFzipper

03-08-2009, 09:57 AM

I have the same mold. So far 21.9 grains of IMR-4064 cycle my Mini-14 and shoot 2" groups at 50 yards. My Mini has a 1-9" twist. I oven heat treat my #2 mix or straight lino. #2 alloy without heat treating would shoot 10"+ @ 50 yards. I felt the same way when I started a month ago. I'm not done yet, hope to get them a little tighter. Keep the boolet weight within .3 grains. Also I nose first size and lube in 2 steps. This seems to keep from bumping the nose.

Larry Gibson

03-08-2009, 02:48 PM

Steve here... I guess from the minimal amount of feedback... I need to get rid of my OldWest mold and buy a 1/12 twist barrel for my AR... and be happy shootin 55grainers... I can do that in my 40x:confused:

WT? No one else has any hot tips

You need to use the least amout of the slowest burning powder that gives reliable and consistant ignition while at the same time gives sufficient gas port pressure to funtion the action. That might be a tall order but with the heavier bullet and keeping the velocity under 1800 fps you may still find useable accuracy. Best accuracy will be in the 1400-1600 fps range but functional reliability my make that a difficult objective.

Larry Gibson

z4lunch

03-08-2009, 10:42 PM

Thanks for all the tips...
I will be heading out to the gun club tomorrow morning with the HK 93, and some 224450's. I loaded some light stuff with 2400,and H4198. I also am trying some H4895 per Larry's instruction.
Steven

exile

03-09-2009, 04:31 AM

I hate to appear stupid, but I did not think you could shoot cast out of an AR. Now I really want a Stag Arms lefty. Probably not in this life though.

exile

Lloyd Smale

03-09-2009, 06:43 AM

cast works fine in an ar. Only thing is a guys got to keep in mind that its dirty and clean his gun after every range session if you actually have thoughts of using it to protect your family. harder alloys and hard lubes tend to help keep the fouling down. One thing i tend not to do is shoot them fast. I think it would take alot to plug the gas tube but my thoughts are that if you get that gas tube real hot and then quit shooting the small ammount of lube thats coating the inside of your gas tube possibly could bake on and eventually over time build up enough to create relibility problems. that and getting the barrel real hot could contribute to leading. I think if a guy took it easy on it with the rapid firing and cleaned the gun including the gas tube after every shot hed never have a lick of trouble doing it.

z4lunch

03-09-2009, 08:54 PM

Steve here... Went to the range this morning with my HK93. perfect day 42f and no wind... 70f would have been better!!!
The rifle shot well with all the loads I tryed but would not cycle the action, which I expected. I fired the rifle at 50 and 100 yds. ALL boolits fired hit the paper.
I will report back with my findings, pics and load data, Tomorrow
I will most likely be ordering a 1/12 barrel for my AR
Side note: The HK was no dirtier than normal...No leading either, and NO gas tube

z4lunch

03-11-2009, 06:01 AM

http://i182.photobucket.com/albums/x33/z4lunch/IMG_0748.jpg?t=1236765684

z4lunch

03-11-2009, 06:06 AM

Steve here... All the groups at 50yds looked OK. I need to try them all at 100 next time. I think I will have the most luck the the H4895. I will post fps afterwork
Steve
http://i182.photobucket.com/albums/x33/z4lunch/03-09-09_1219.jpg?t=1236765943

z4lunch

03-11-2009, 06:07 AM

I'm using a 4x Hensoldt, at 100yds with old eyes.
The H4198 and 2500 was around 1600fps
the H4895 i think was just over 2000fps
Steve

z4lunch

03-15-2009, 08:36 PM

Steve here... went out to the range again with my ar-15... I shot 18 grains of H4895 with my Oldwest 70 grainers that waterdrop at 64. The rifle would not function with the factory spring but i was able to get it to function with a 223, and 9mm reduced power spring from Wolff. I tried both and the 9mm spring seamed a little softer, and worked more consistent. The rifle would not go into slide lock consitently, but functioned and ejected the brass in a small circle 4 to 5 feet away. The groups tho at 50yds were pathetic... 5 to 7 inches. From this test and testing my 1/12 twist HK93 last week...I plan on ordering a 1/12 twist barrel for the ar.
Steve