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178 is fine just use 175smk data and play with seating depth until it's accurate. 208 is a bit difficult since you need to load it long and use slower powders like RL17 to get it to perform. It's more for bolt guns.
 

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I've loaded the 178s before and liked them but I've never tried the 208s. I would recommend not exceeding about 2400 fps with the 208s and no more than 2550 fps with the 178s (assuming IMR 4895, a COAL of 2.80", and low volume cases).
 
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Regulated Gas plug mod for anything over 178 if you use "normal" powders is what I have heard. I don't know a great deal about going heavier. Just enough to be dangerous. Def.not enough to give reloading advise.
Older salt on the forum will hopefully chime in and give ya some sound informative advise?
Youtube tonyben and search for a gas plug video....or PM him. He is the M14 YODA.
RAMMAC here in the forum is the same for reloading.

Dutch
 
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I would never shoot those in any guns. Send them to me and I'll dispose of them for you so nobody gets hurt.
 

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I've never had a problem loading my 168 and 178 grain Amax's to normal lengths, in fact I usually seat mine to 2.82"
 
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I've never had a problem loading my 168 and 178 grain Amax's to normal lengths, in fact I usually seat mine to 2.82"
I have been loading 168 gn BTHP from Hornady for a while now. Actually, I started this loading business 6 months ago. Made a mistake and bought some moly AMAX bullets when I wanted the regular copper covered ones. Anyway,
I loaded some 168 gn AMAX moly's. Ended up with a C.O.L of 2.83ish. Thought about adjusting the seating die. Checked to see if the fit in the mag instead. They worked just fine. So, this business about having to seat Farther into the case...ehh. At least this is what ive found. Jmo

Dutch
 
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The 178 A-Max is longer than the 175 SMK. If you load to the same OAL (magazine length), the A-max will be sitting deeper in the case, increasing pressure. RNGR2
The differences aren't enough to worry about, no more than about 1,000 PSI and maybe 10 - 20 fps.
 
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I don't have my notes with me but I shot some 208gr amax with re17
Out of my m1a. I had an adjustable gas plug it it seemed to work well. I was still in my load development so I put about 50 down the barrel at a little over 2400 fps. The load was compressed at mag length using lc lr brass. When I get back for good I'm gonna try some win brass and 2000mr to see if I can run it accurately at around 2450 fps without running a compressed load. There are a lot of solid loads out there to run the 175 smk/178 amax. The 208 amax was extremely accurate out of my 308 savage.
 

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I'm working out loads with the 178gr bthp from Hornady. Powder I'm using is IMR4895. Brass I used last was Hornady nickel plated. Primers were CCI bench rest. Seating depth was 2.80" col as tested. I started out with a powder charge of 41.5gr and I got speeds just over 2400, about 2420fps or so. Next I tried 42.0gr of the same. My velocities increase to 2480fps or so. Faster improved grouping at my 100yd target, but I think I might clean it up some more getting the velocities up to my 2550 goal. As it was it shot 3/4" @ 100yds.

My rifle is a SAI clone I built. I'm running 1-10" Krieger heavy contour barrel and my piston is a Sadlak TiN nm grooved piston. Best factory loads has been 168gr Amax beating the 175 Blackhills gold 175gr smk by .1" @ 100yards. Unfortunately I haven't had any 178gr Amax to try. But these bthp from Hornady show real promise and it has my interest.

As for the 208gr, not sure I would ever try those in my m21. In my bolt action I would though. I think you would be too limited working up loads for a bullet weight like that in a platform such as a m1a.
 

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The great thing about the 178s is that you don't really need to kick them up as fast possible, they have a great BC value and their mass keeps their trajectory flat and they buck the wind well. You can drop the load and get very good groups, as good or better then a hot load but without beating the rifle as hard.
 
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Discussion Starter · #17 ·
The great thing about the 178s is that you don't really need to kick them up as fast possible, they have a great BC value and their mass keeps their trajectory flat and they buck the wind well. You can drop the load and get very good groups, as good or better then a hot load but without beating the rifle as hard.
RAMMAC, do you happen to have any load recommendations? If not, can you point me to a powder that might work well with this weight bullet?
 

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I haven't been able to get the time to optimize the load but right now I've got a load using;

Lapua brass (higher volume than most cases so most other brass will result in slightly higher velocities)
Case trimmed to 2.005"
Cartridge overall length 2.83"
Federal 210M primer
178gr Hornady BTHP (not the Amax)
39.7 grains of IMR 3031 (the only other powder that I'd be interested in testing is Accurate 2495)

It's a nice easy load that only produces about 50,000 PSI of chamber pressure and a muzzle velocity of about 2550 fps. It's still super sonic at 1000 yards and while it wont produce groups much better than 1.5 MOA I was able to hit pretty well at 1100 yards on a 32"x32" steel plate.
 
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