Advice please on my finicky .308...

[Duff]

I have been tinkering on and off with a .308 for about a year. It is a 20" heavy barreled savage with 1x10" twist. I have tried several loads using 125 TNT's, 155 MK's, and 168 Hornady match. Surprisingly, the TNT's have given me the most consistant results! /ubbthreads/images/graemlins/crazy.gif I have tried different powders, seating depths, ect. and I still get very inconsistant results. Some groups shoot 3/4 moa and the next will open right up. It just doesn't seem to like much I've fed it. Is this because it has a short barrel? or have I just not found would it likes? I have some 175 MK's on order and hope to give them a try next week. Any suggestions? I had the best luck with Benchmark with the 125 TNT's, and tried BM, Varget, and 4064 with the 155's and varget and 4064 with the 168's. Where do I go next?

 

[royinidaho]

Hmmmmmm,

So far nothings worked, correct?

I'd check some mechanical things about the rifle.

Mess this the receiver screws and see if you can "feel" or notice any movement as they are alternately loosened and tightened.

Ensure barrel isn't is bedded properly. 20" incher otta be fully free floated, I'd think.

Thoro cleaning clear down to the metal. All copper and powder residue gone. Then look down the bore and see if you can see any anomalies. Maybe there's a gopher hole down there someplace. /ubbthreads/images/graemlins/grin.gif

Check the crown. Was the original barrel length 20"?

After a good hard "look over" and there's nothing obvious then look at the scope and mounts.

After all of that then look at the reloads. Are they straight regarding roll out.

The above ought to take quite a while. If nothing noted by then, you can go to the next step. /ubbthreads/images/graemlins/crazy.gif

 

[Duff]

Sorry if I was unclear, the rifle is bedded in a Stockade gunstocks stock with barrel completely floated. The original lenght is 20" and the crown "looks" fine. I've checked the action screws and no binding or anything unusual. Had the scope off and checked the bases/rings. I clean it with shooters choice and Kroil after about 20 shots. I would assume that it is the loads? (assumption is the mother of all screw ups, I know /ubbthreads/images/graemlins/smirk.gif) I don't know what else to do, except try a different bullet weight all together. I have had some success in getting the 125 TNT's to fly consistant (3/4-1 moa) but not great, the other bullet weights are just not consistant.

 

[jb1000br]

Try benchmark with the 168's , bout 42gns will be close.

JB

 

[billpock]

I'm no expert, but I have been working on a 308 that I bought a while back. And to take my handloading out of the equation, I bought a couple of boxes of Federal Gold Medal Match.It gave me sort of a baseline. Have you tried any foctory match ammo?

 

[Duff]

No, I have not bought any factory match ammo-kinda against my religion /ubbthreads/images/graemlins/laugh.gif Maybe I'll give that a try. I just haven't bought any factory rifle ammo in years.

 

[billpock]

Duff, I'm with you 100%. I do all my hunting and shooting with hand loads. I just wanted to give myself some idea of what the rifle could do. It gave me something to shoot for. It shot well with the GMM. I have been able to do a little better with hand loads and am still working on it.
Good luck.
BP

 

[Rheinhardt]

Regarding seating depth: there is an optimal depth. You need to seet the bullet such that your arent jamming the bullet into the lands and your not way away from the lands. I would suggest fireforming all your brass, that is to fire any old load in the gun to fit the brass to the dimensions to your chamber. Then I would take whatever bullet you want to try and seat it kind of long. Put the bullet into the chamber and close the bolt. Pull the bullet back out and look and see any marks on the copper jacket that are scratched from touching the lands. Mark it with a black sharpie, lower the seating depth ont he die a little bit and repeat. Repeat this process lowering the bullet only a 1/8-1/4 turn on the die screw. What you want to do is get the bullet so it is JUST off the lands, as close as you can get it without the bullet actually touching. This will ensure the bullet hits the lands perfect but the bullet isn't under any force from the lands allowing the bullet a mini head start so we dont generate excessive pressure at the get-go.

Regarding powder charges: Many people simply start way too hot on the powder charge. I'd start at the very low end of the spectrum from your reloading manual and work up in half grain increments. The most accurate loads I develop are mostly at the low end of the pressure scale. if your using military brass for reloading, I would say take a grain or 2 off the lowest indicated powder charge and start from there as military brass tends to be thicker (less internal volume so you get higher pressures with less powder).

Regarding bullet choice: some guns like certain bullets more then others. You maybe have to try lots of different bullets with lots of different powders before you find something that works. I once had a winchester model 70 in 308win that liked 110gr bullets and 180gr bullets and everything inbetween shot like crap. **** it I could figure it out, but thats what it liked. That 1 in 10 twist on that savage is really fast even for a 20" barrel. I'd try something like the 175gr-180gr matcking. Could be the lighter bullets are getting to much spin.

Regarding barrel conditioning: if you havent put alot of ammuntion thrut he barrel yet, there are lots of methods out there to properly condition the barrel prior to testing handloads.

Regarding mounts/optics: there is just so much that can go wrong here but the problem I see the most is people not lapping rings or using foam ring tape prior to clamping that scope down. the 308 doesnt recoil much but repeated recoil over time can compound and cause problems. (TPS/Mark4/Badgers are the only rings in my opinion that do not need to be lapped).

Regarding trigger: while it doesnt effect inherent accruacy it does effect the shooters ability. Factory trigger pulls are an atrocity that only serve to satisfy liability lawyers. Most triggers in modern firearms can be adjusted without the need to pay a gunsmith. I'd suggest taking it down to 3 pounds +/- if you havent already. Accutrigger on the savage is good stuff.

Regarding shooting: I always load 5 shots for a particular powder charge and take the best 4. Make sure your brushing the barrel between each shot and even with that heavy barrel I'd give it 5-10 minutes between shots to cool down between shots.

Just some pointers. I have yet to find a modern rifle in good shape that can't get to shoot thru a dime all day long at 100 yards. But sometimes you just need to play with alot of bullets and alot of powders till you find that magic combination.

 

[jb1000br]

[ QUOTE ]
Regarding seating depth: there is an optimal depth. You need to seet the bullet such that your arent jamming the bullet into the lands and your not way away from the lands.

[/ QUOTE ]

That is the absolute WORST place to seat a bullet! Bullet and seating variance along with throat erosion will position every round differently from the next by some amount.

YMMV,
JB

 

[Duff]

jb1000br: What would you say is the best method of determining seating depth (for a starting point)? Into the lands? or deeper? I've ususally had good luck just off the lands as mentioned above.

 

[ILIKA308]

I WOULD BE WIILING TO SAY YOU HAVE SOME SORT OF A RIFLING OR TWIST PROBLEM WITHIN THE BARREL. YOU NEED A GOOD BORESCOPE TO CHECK IT OUT.

 

[royinidaho]

Duff,

Here's what I do to measure seating depth.

Using a full length resized unprimed case.

Use cutter wheel (chop saw wheel) on dremel tool and cut 3 equidistant cuts from case mouth to bottom of neck/top of shoulder.

The idea is to make a case that will hold a bullet a minimum amount. If too tight bullet will stick in rifling. It too loose it'll fall into the case.

Next, insert bullet of intrest into the case, just enough to hold it then,

Carefully chamber the case w/bullet. Close the bolt.

Carefully remove the cartridge.

Waa Laa, you now have a cartridge with the bullet seated by the rifling. It neck tension is correct it will be just touching the taper on the rifling (leade I think its called)

 

[Rheinhardt]

If your using any quality bullet manufactured by sierra, hornady, nosler the tolerance on the ogive is acceptable. That why I said you want to leave it a close to the lands as possible without jamming. Leave far enough away so as to compensate for some of the natural fluctuation in bullet dimensions. I've used this method for years and its documented in several brand name reloading manuals that this is where the bullet should be seated for optimal accuracy. I can refer you the specific page numbers in my Hornady, Speer and Sierra manuals if you want.

I will give you this: if you are loading for any chamber that has an excessively long throat such as a rifle barrel thats had quite a few rounds put thru it or a military rifle barrel then you might want to seat to a standard OAL so you can feed the cartridges into the magazines effectively. I will also conceed that anyone seating bullets in this manner would be wise to check the throat erosion every thousand rounds or so to adjust seating depth as the the throat will wear from shooting. But as far as the *worst* way to seat...the worst would be seating way too deep, generating excessive pressures and possibly injuring yourself and anyone near you.

 

[green 788]

Have you heard that old shop worn adage that "all rifles are different?" Well, they are.

Just like all kids are different.

But you know what?

All kids are not that different.

Some kids will eat their green beans, some won't. Some like corn on the cob, some can't stand it...

However. /ubbthreads/images/graemlins/smile.gif Show me a kid who doesn't like chocolate ice cream and I'll show you one twisted little odd-ball (not meaning to insult anyone's kid here, just dealing with facts). /ubbthreads/images/graemlins/laugh.gif

But you're in luck!

There are chocolate ice cream load recipes for your .308!

No kidding. Federal Gold Medal is usually one such recipe. And there are others.

I'll mention a few here for you. What I'm telling you is that if your Savage won't shoot decent groups with the following load recipes, it is, well, one twisted little odd ball rifle. /ubbthreads/images/graemlins/smile.gif (Not really, it's just got a problem).

1. 168 grain match bullet. 43.6 grains IMR 4895, Federal 210 primer preferred, win or Lapua case.

2. 175 grain Sierra Matchking, 42.5 grains IMR 4895, rest the same as above.

3. 180 grain bullet, 44.2 grains of Varget, CCI 200 or BR-2 primer.

4. 175 grain Sierra Matchking, 45.0 grains Varget, rest as above.

5. 125 grain bullet, 51.4 grains W748, just about any primer you can name.

Seat the bullets a caliber's depth into the case. Don't worry about distance to the lands yet. A caliber's depth seating will work fine.

If you don't have any IMR 4895, you should get some. However, you may find that 43.5 grains of IMR 4064 does very well with the 168's, as will 43.8 grains of Varget. Only problem with Varget though is its burn rate seems to be all over the map these days. So I'd rather see you use the IMR powders. Make sure your lot number of Varget doesn't end with "4133". If it does, it's closer to 4350 than Varget. Hodgdon will replace that lot if you send it in...

See what you can put together from the list above and give it a try. If you're only willing to try one of the loads, go with the 43.6 grains IMR 4895/168 match bullet load.

One last thing. Unless you've got meticulous load notes, you may think you've covered some of the load combinations above, when in fact you'll have missed them. So don't necessarily assume you've "been there, done that."

If your rifle fails to shoot well with these load recipes, I think it's safe to say that there is definitely a problem with the mechanics of the rifle...

For more on the reasoning behind these loads, which I call OCW (Optimal Charge Weight) load recipes, you can check my website: www.clik.to/optimalchargeweight

Good luck. Keep us posted.

Dan