I spent about 12 hours at the range this weekend with my new 308. I shot various loads with some of the best being 168 gr Sierra Matchkings over 4064, 168gr Nosler J4's over BLC2 and 165gr Sierra HPBT Gamekings. Nosler 180gr BT's over H380 were pathetic as well as 165gr Deep Shoks and 150gr Mag Tips. I shot quite a few groups with two bullets touching and one off by .5 - .75 center to center. Most groups were sum-MOA and those that were not were 2+ center to center.

I loaded the match loads at 2.800" and the hunting bullets at the book OAL.

I noticed that groups started to open up on the match loads (best accuracy at 2500 +/-) when I increased the powder charge so I am thinking it is a matter of adjusting the seating depth.

Question: Do I move the bullet out to the lands and start over with the powder charge; or, start seating the bullet longer?

If seating the bullet longer, at what increment?

[ 09-02-2003, 21:38: Message edited by: Oilburner ]

Oilburner, BTW, What are you shooting for a rifle? If you don't need to use the magazine, I'd seat the bullets about .010" off the lands, I know with the 168MKs in my 308, I'd have to seat the bullet out to like 2.930" to be .010" off the lands, (Rem. chamber) and I'd be using 42grs. of RE15 also, great powder and measures better than 4064, albiet appr. same burn rate as the RE15, and isn't temp sensitive either, which might come in handy in TX. If your shooting a sporter rifle, don't expect the accuracy to get much better with the MKs, you might want to shoot 1 shot and wait about 3min. for the next etc. etc. but too, that may not get your groups smaller either, I tried that with my 708 S/S Rem. with 120gr Hor. HPs with 42.5grs. RE15, got 13/16" for 5 shots, but I've shot in the 4s with the 150MKs with 39grs. RE15, all bullets .010" off the lands, Good shootin', Jay

>best being 168 gr Sierra Matchkings over 4064<
That's pretty standard in this caliber.

>shot quite a few groups with two bullets touching and one off by .5 - .75 <
You really can't tell much with 3 shot groups. 3 shot groups will only separate the really awful from the posible. Switch to 5 shot groups and when you find a really good 5 shot group, shoot at least 3 of them for final results.

> loaded the match loads at 2.800"<
That is normal for this caliber. Sometimes this is rifle specific, too, as already mentioned. At least these should function well through the magazine of any .308.

>(best accuracy at 2500 +/-)<
Very typical. There is a "sweet spot" at about 2550 fps when using this caliber. With your bullet, the 168gr SMK, that is good out to 600 yards if the velocity spread in your rifle is not too great. This sweet spot shows up quite often.

There is no absolute rule about just how long the ammo should or should not be, but here are a three provisos: Ammo must function through the magazine and not tie up your rifle. Ammo must have the bullets enough short of the lands to avoid bullets sticking in the lands and tying up your rifle. The bullet must be seated with enough seating depth to insure good bullet hold for proper ignition and rough handling. 0.0010" increments are as good a starting place as any. Shoot 5 shot groups and series of 3 of the 5 shots groups. Besides improving your statistics, its good practice.

Good luck, be safe.

I especially like using IMR4064 and the Sierra 168gr MK. It's a great combination in most guns.
Now, can you reach the lands with most bullets? I measured all of mine with the Stoney Point OAL guage and was surprised to find that most wouldn't even reach the lands in my Browning Micro Medallion. You may have to resort to a longer bullet although the 168gr Sierra is one of the longer ones at 1.204". The Lapua Scenar 167gr. is a bit longer at 1.227". The Nosler 165gr Bal. Tip is about the longest at 1.292". Some of the bullets you mentioned are hunting bullets, so I wouldn't expect match accuracy. You may have to play around with this one a bit. I agree though that your best accuracy may well be slightly touching the lands. Best wishes.

Cal - Montreal