imr 4064 308 help

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nova_scotian_guy

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ok i just started to reload for my 30 today

shell sized to 2.012(+/- 0.0005)
amax 168 grain
cci 200's primers
imr 4064

reloading tools
rcbs 5-10 scale (checked 3 weights to confirm accuracy 10g,50g,60g)
lee pacesetter die set


started off with 42 grains of imr 4064 ... it seems like the powder is being compressed by the projectile .. i loaded up 5 or so when i noticed this ... if i shake the shell after the bullet has been set you can hear nothing on the inside .... also on the imr website (or a chart i was looking at ) it said to sit the bullet at 2.800 which i made up 5 dummy shells at first to check seating depth is correct (2.799-2.801) now the 5 i loaded up with powder all measure about 2.809-2.813 ... does this mean i should be seating the bullets 2.815 so there not compressed or did i manage to screw something up ?
 
I just checked what some guys are using at Sniper's Hide, an online precision rifle forum, look it up. One fellow was using Hornady AMAX 168gr. with 44.5 grains of IMR 4064 and a COAL of 2.810, while others are using SMK 175's with 43.4gr of IMR 4064 with COAL of 2.830.

My personal experience has been to use 42 gr. of H4895 with 168gr Hornady Match HPBT's with good effect with no issues of compressed loads. I can't recall the exact COAL at the top of my head. Each rifle will have a unique throat length, thus accomodating various length projectiles and their ogives. Some folks say that you should load as long as possible, while others not. My personal preference is to load a dummy round long, uncrimped, take the firing pin spring out of your bolt and determine when the lands start biting into the ogive of you particular bullet, I back off slightly from there by a few thousandths and that is how I determine my COAL for any particular bullet for a particular rifle. It has worked well for me thus far. As you probably know, you definitely want to make sure that the round has sufficient pressure to seal the breech while also avoiding excessive pressure.
 
30 what? Assuming .308, you're a full grain below minimum for a 168 for starters. 168 grain IMR4064 loads are nearly all compressed and is nothing to worry about. Compression starts well below a max load(45.0 for IMR4064), but if you're getting different OAL's you have something loose or the case lengths aren't the same.
Either way, fiddling with the OAL is something done after you have a load. And every rifle chamber is different. The OAL that works in your rifle will not be the same as any other rifle, so start with the 2.800". Work up the load then fiddle with the OAL. It's not always required either.
 
Well - As a rookie - you wont be able to hold 3 thou off the lands, guaranteed. Give yourself more margin - go with COL of 2.80. Additionally, your "to the lands " test may be erroneous.
 
Need some more info, what brass are you using? I just loaded a bunch of 168 Amax's over 42.0 gn of IMR4064 in federal brass to 2.800" OAL with no issue for compression 2 days ago. You shouldn't be compressing the powder yet at that charge.
 
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