Trouble with 308

[lwink]

So today at the range I tried out one of my first handloads. Now these were actually loaded under the supervision of an experienced and quite accomplished reloader, so I know that inconsistency in the bullets is not to blame -- with that preface here is the deal. I tried out a 5 shot group with 168 smk's over 42.0 grains of RL 15. I thought it was a good place to start, and I guess it was -- no pressure signs at all with a .015" jump to lands. They shot OK, somewhere in the low to mid .4's. Next, just for fun, I shot a group with some factory Hornady BTHP (168's as well) that I had for sighting in, which was a .227" -- very happy with that one off a bipod and rear bag. So where do I go with my reloading guesses in the next few days -- should I back off the lands a little more -- the Hornady's have a .023" jump. Without a chrono I can tell the reloads are going faster (they are grouped about .75" higher than the hornaday factory ammo). What is proper procedure now -- should I play with my jump to the lands, go closer or further or try both? Also, could I be in a weird in between speed, where I could back off the charge and match hornady velocity and tighten things up, or go up to say 42.5, 43, 43.5 and try out these increased velocity loads? Like I said, I will be reloading some more trials up with RL 15 and 168 SMKs, just need to hear maybe 5 or 6 rounds to experiment with based on the info I've just given. Hope to make more estimated guesses on what might shoot better rather than just throw lead down range and hope to get lucky. Thanks!

[Uncle Jack]

In a situation like that, I would try adjusting the powder up and down .2 of a grain until I found the best group. Then I would start adjusting the ogive seating depth by .005 at a time.

It sound to me as if you are pretty close already.

uj

[RKG]

While I don't disagree with Uncle Jack's suggestion, an observation may be in order:

The difference between a couple of 0.4 MOA groups and one or two 0.25 MOA groups is so small that it is likely the result of factors that are random and hard (if not impossible) to control by reloading. For example (and only for example), subtle differences in wind could cause that small difference. Differences in barrel temperature could cause that small difference. Small differences in cheek weld could cause that difference, particularly if the scope is not perfectly free of paralax.

So have a ball, but don't drive yourself nuts striving for unachievable perfection.

[Dennis]

First, what exact 308 are you shooting?

I you like SMK's (great bullet, I use them) them check this link out!

http://www.6mmbr.citymaker.com/f/Sierra308Win.pdf

Personaly I use 168SMK's with 43.0 of RL15, however start at 41.5 and work up. Sierra states 42.0grns is the key, so maybe play with the lands! Every gun is different.

I HAVE HAD MY BEST GROUPS PUTTING THE BULLETS ON THE LANDS!!!!!!!

You might try this, then maybe back off .010 and .015, any higher MY groups started opening up.

I am going shooting today, but experiminting with Nossler's!

[okie2]

ALSO TRY THIS
hornady 168 Amax and sst's IMR 3031 39.5 grains this load has shot very accurate in every 308
I have seen it used in and 39.5 of imr 4895 is about as good.
my savage 308 put 10 shots in .5 inch at 100.

[lwink]

This was with SMK's -- went to the reloading room and kept everything at .018 off still, but went from 41.5-42.5 of RL15 and the same with Varget, also loaded up a couple Amax loads with RL15 and Varget. Will get shooting next week and see if they'll tighten up. I would like to try jamming a couple into the lands -- how far do you back the powder charges down to avoid getting too much pressure?

[Dennis]

Assuming you are shooting a heavy barrel 308,

If it were me and "ONLY" me I would back off the charge about 10% or start with the min load recommendation.

I would jam into the lands about .010, again only on a heavy barrel.

Look for signs of over-pressure.

I do this with Berger's sometimes, but I have my most luck on the lands (.000), Same with Sierra bullets.

Today I had my best groups with Berger 190 VLD's 42.8grns Varget! Also SMK's 175 with 43.5 gr of Varget did pretty good also.

I am getting ready for a 600yd private match Thursday!

I also shot a few Federal 175HPBT which measured .050 off the lands, they held a pretty good group. I wish I knew what primer and charge they used! Federal is amazing sometimes.

[pdog06]

This was with SMK's -- went to the reloading room and kept everything at .018 off still, but went from 41.5-42.5 of RL15 and the same with Varget, also loaded up a couple Amax loads with RL15 and Varget. Will get shooting next week and see if they'll tighten up. I would like to try jamming a couple into the lands -- how far do you back the powder charges down to avoid getting too much pressure?


According to my book load range for Varget and 168smk's is 42-46gr. I started mine at 42 and loaded up 10 rounds each from 42-44gr in .5gr increments. At 44gr I still had no pressure signs.

Then I re-shot the same ladder test at 200 yards. The 42gr shot the best at 100, but was the worst at 200. I ended up using the 43.5gr charge, seated .015 off the lands. I have shot many groups in the .2's with it, but avg in the mid .3's.

[Dennis]

pdog06, How do you like your McGowen Barrels?

[Dennis]

I opened up a Federal 175HPBT M118. It has 38.5 grains of powder, .050 off my lands, but shoots sub moa @ 100??????????

I opened up a FGMM 175 and it had 43.2 grains of powder.

Both powders looked the same, still havn't figured out which one it is!

[Dennis]

I just loaded up a few Berger 175 VLD with 43.5 grns of H4895 seated .005 into the lands. Going to try them out at 600yds tomorrow.

[Uncle Jack]

Dennis;

"I would jam into the lands about .010, again only on a heavy barrel."

Are you saying that you seat the bullets .010" longer than ogive contact?

uj