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[300Blk]

175 may technically cycle, but I don't think it would be with the proper cyclic rate. I would stay at 200 or more. If you do want to try lighter bullets, then use the lightest buffer.

[Overton-AR]

Well I am completely at a loss. I have only been reloading for a few years
so maybe some of you have seen this, but I haven't.....

No matter what I try, I cannot get the speed DOWN on my 220 SMK loads.
Here is what I have done so far......

Powder.......Bullet.....Charge......C.O.A.L......Velocity
A1680 .... 220 SMK ..... 11.5 ........... 2.2 ..........1188
A1680 .... 220 SMK ..... 11.1 ............2.2 ..........1183
A1680 .... 220 SMK ..... 10.5 ...........2.25 .........1275
A1680 .... 220 SMK ..... 10.2 ...........2.25 .........1288
A1680 .... 220 SMK ..... 8.5 .............2.25 .........1256
A1680 .... 220 SMK ..... 8.2 .............2.25 .........1265

I am completely lost as to what to do next. My slowest loads so far have been
the biggest charged loads. From 10.5 gr. all the way down to 8.2 gr. I only saw
a fps change of less than 20. I am really wanting to get sub sonic with this
powder. I have other powders on hand to try, but don't know where to start.

Others I have on hand are....

AA-2230
Hodgdons 322
Hodgdons 335
Ramshot TAC

Any suggestions as to what to do with my current A1680 loads would be preferred,
but I will try the other powders if I need to.

[tmbg]

Overton,

Interesting... that's closer to what quickload predicts for that load... I haven't been able to test it yet, so I wasn't sure how that was going to work out.

Very odd that the lighter loads are FASTER

[Overton-AR]

Overton,

Interesting... that's closer to what quickload predicts for that load... I haven't been able to test it yet, so I wasn't sure how that was going to work out.

Very odd that the lighter loads are FASTER

I know, I am beyond baffled at this point.

[300Blk]

That is strange. Slug your bore and measure the bore and groove with a micrometer.

[LYNRDSKYNRD]

Just for a reference what are you shooting them out of...AR...Bolt gun...Barrel Length??

[Overton-AR]

Just for a reference what are you shooting them out of...AR...Bolt gun...Barrel Length??

Sorry, its a 10" Noveske barrel.

[ahm]

try putting up a blast shield mid way between the muzzle and the chronograph. Your loads may be subsonic but the muzzle blast could be tripping one of the screens. At the point when you do develop a subsonic load (if you haven't already), the blast shield should be considered essential. It's not needed for supersonic loads. The blast shield can just be a piece of cardboard with a vertical slot about 2" wide by 9" tall. Are you about 15 feet from the chrono?

[Overton-AR]

try putting up a blast shield mid way between the muzzle and the chronograph. Your loads may be subsonic but the muzzle blast could be tripping one of the screens. At the point when you do develop a subsonic load (if you haven't already), the blast shield should be considered essential. It's not needed for supersonic loads. The blast shield can just be a piece of cardboard with a vertical slot about 2" wide by 9" tall. Are you about 15 feet from the chrono?

No, I am about 4 or 5 ft. from the chrony.....you might be onto something.

[imyomama]

try IMR 4198 ? mine is sub in 9" barrel with 10grains... try 9.5 maybe ?