Speed Kills . . . Accuracy???

21 July 2002, 19:33

<.>

Loading up some .223 Rem. to fire form in .223 Ack. I first loaded for speed and was pusing 55 gr Win FMJ at about 3100 fps. Groups were literally a foot wide at 100 yds.

Then I opted to fire form "on the cheap" with these bullets. 23 gr of H-335 or 26 gr. of BL-C2. Pushing these pills at 2800 fps or so. All of a sudden the groups are closing up to sub MOA. No fancy tricks, no neck turning, or neck trimming . . . just seated at 1.760" (I think) and shooting mixed date Lake City brass.

Rem. 700 PSS with a AI chamber, set back, rechambererd, shortened to 20" and recrowned. Holland recoil lug.

55 gr. Win FMJ are running $4.96 / 100 here abouts. Nice ammo for horsing around or fire forming. But I think at 3100 fps, they come apart with this 1:9" bbl.

21 July 2002, 19:47

<Big Stick>

I seriously doubt,with that mild of a load,your brass is even close to being fully formed.

I form 55's,with a minimum of 25.0grs of H-335,with land engagement and moly.

Further,I've yet to feed a barrel that is capable of sub MOA accuracy,a good bullet/powder combo,that yielded 1 FOOT groups at 100yds! Be it a forming operation,or not.

Certainly you do not infer they(W/W 55gr. FMJ's) "come apart". As in the bullets unraveling,at those sedate velocities(3100fps)? I shoot them in HOT 22's at 4000fps and they've the mustard,to weather that storm.

Try again,on ALL counts..............

21 July 2002, 20:06

<.>

quote:
Originally posted by Big Stick:
I seriously doubt,with that mild of a load,your brass is even close to being fully formed.

I form 55's,with a minimum of 25.0grs of H-335,with land engagement and moly.

Further,I've yet to feed a barrel that is capable of sub MOA accuracy,a good bullet/powder combo,that yielded 1 FOOT groups at 100yds! Be it a forming operation,or not.

Certainly you do not infer they(W/W 55gr. FMJ's) "come apart". As in the bullets unraveling,at those sedate velocities(3100fps)? I shoot them in HOT 22's at 4000fps and they've the mustard,to weather that storm.

Try again,on ALL counts..............

"Mustard" is that spicy yellow/brown stuff you put on hot dogs. It's "muster" -- which is "callng a roll of troops to duty."

So, .223 Ackley will be just fine whether fire formed or standard .223 Rem config. Both shoot with good accuracy in the Ackley chamber. Where it gets hairy is neck turning the brass before it is fully formed. This results in "doughnuts," etc. in the brass neck.

Moly is going to reduce both velocities and pressures. This will affect fire forming, and every other aspect of the paradigm.

I'm not sure what's going on with the bullets. At 3100 fps or better they spread all over the place. At 2850 or so, they group nice and tight. I'll concede that I had an inch removed from my bbl. at the end where some fool had gouged the bore. Maybe that's the problem. Could be the problem, but it doesn't seem likely.

I'm gonna bet though . . . that these load are fully forming the brass. Let me put a micrometer on my test results and get back to you.

With some matched brass, neck turned and match quality bullets (Hornady), this gun turns out .33x MOA at 3850 fps in a really consistent manner.

You likely know what you're talkng about, but I'm no rube either.

[ 07-21-2002, 11:08: Message edited by: Genghis ]

21 July 2002, 20:32

<Big Stick>

I'll save space and cut to the chase.

You say the SAME barrel will shoot either 1/3" groups(at 3850fps) or 12" groups( at 3100fps)100yds?!!?.............

22 July 2002, 09:53

Eddie

quote:
55 gr. Win FMJ are running $4.96 / 100 here abouts.

I've seen them frag in 1:7 barrels, but not in 1:9 twist. I've never been able to get a reasonable group with the Winchesters in my ARs. I've had good luch with the Hornady 55FMJs and H322. I think I paid about $45 for the last K I bought.

Eddie

[ 07-21-2002, 12:53: Message edited by: Eddie ]