.308 seating depth Q's

[jhord]

I have a new-to-me Remington 700VS. My Hornady OAL gauge mockup case arrived today, so I set about getting some measurements. Using the Hornady OAL gauge with .30 comparator and a Sierra 168HPBT, I'm getting a OAL of 2.380" with the bullet against the lands. Whoa! For reference, the Federal Match w/ the same bullet I bought to shoot until I could get handloads figured out measures 2.225". So with the Federal, the bullet is jumping .155"! (and it shoots well) I had figured on building up some loads with a .030" jump, but doing this would mean that only ~ .135" of the bullet's bearing surface would engage the case neck. That doesn't seem enough to me? What's the least I can get away with, any rule of thumb? I know "they say" you should seat it the bullet's diameter but that will be a huge jump in this rifle.

 

[dreever]

The C.O.A.L. of the .308 with a 168 gr bullet should measure 2.800 and I'm sure in a factory chamber this will get you no where near the lands. If you are going to mag feed you will be limited by whatever your max mag length is minus .005+ to allow all rounds to fit the mag. The .308 with non VLD bullets is pretty forgiving in regard to bullet jump so don't worry to much about it. I've also found the Hornady type guage to be less than accurate in determining OAL. I use the old take a fired case with a minimum of bullet tension seat a bullet a little long and let the bolt do the final seating method. Then I play with seating depth from there.

Danny

 

[DHD]

You will find that you will not be able to seat the bullets close or jam them in a factory Remington chamber or this has been my experience with more than a few Rem 700's. You will find that the mag box will be real close to 2.825" +/-. There is your problem, or not. I load my 308's as close as I can get to this number so they feed good from the mag (I WILL go to a Badger M5 soon!). If you are using SMK's keep in mind that they will vary in nose length so factor this in when seating the bullets. What I mean by that is they are not all exactly the same. Some longer by a few thou and some shorter by a few thou. Get a length that they will all fit in the mag, and don't look back.

Or just load them plenty short in the 2.800" - 2.810" range and shoot. As was already posted, the non VLD's are very forgiving. VLD Bergers don't shoot so good in my rifles and I won't load them long, but that's just me.

My $.02 and all that.....

 

[fdshuster]

You have a typical factory rifle with a deep throat. The factories have to make the throats deep enough to chamber factory ammo, using those with the longest, heaviest bullets available. Trying to seat a short, lightweight bullet at a reasonable distance from the lands will most always be a problem. The good news is that from my experience, the 308 is one of the least critical ctgs. for bullet seating depth, almost anything seems to work. It's also probably a "lawyer thing" for the factories, since a ctg. with a good amount of freebore will have lower pressures. The VLD bullets will be even more difficult to seat close to the lands, one of the reasons I prefer the Sierra MatchKings, ( #2190, #2155, #2200, etc.). You'll have to try various seating depths to determine which is best for your rifle. If you want magazine feed, then that will be your limitations.

 

[jr600yd]

Danny's right about the C.O.A.L. Remington barrels are known for thier long throats. Years ago a guy told me Remington throated thier 308/30-06's for the 220 gr round nose bullet. Maybe that explains it? Anyway, like they say load the 168's to 2.80 and let 'em fly. This bullet is forgiving as to jump. You may be surprised how accurate they can be with the right load. Like Danny, I haven't had good results with the Hornady guage. I use the Sinclair tool. "Shoot it like you stole it". If you decide to shoot VLD bullets you will have to load them long and I bet they won't function thru your magazine. They will still shoot very well you'll just to load one at a time. Down the road you'll buy a new barrel and then you can worry about this stuff.

Good shooting, Jim

 

[jhord]

Hi all-

Thanks for the input. I should have specified, I'm developing handloads for target/fun shooting and will single load most of the time. I can build up a few special for mag loading. The Federals I have do measure 2.800" to the bullet tip. The measurements I gave above are to the ogive, using a .30 cal comparator body on my calipers. I agree the Hornady tool can be a little tricky to use but I always check at least 5x. On this gun I am getting the same reading every time. On some other guns I have had troubles with lands that stick up a bit "proud" of the others and make the bullet sticky and hard to find a consistent depth. (if that makes any sense) But on this one, the bullet is seating nice and solid in 1 spot every time.

Anyway, it sounds like I don't have much of a problem. I'd still like to seat the bullet out more. I found a reference to "half the neck length" being a good minimum bullet to neck engagement. So if I go by that rule of thumb I can reduce jump to about .050" by my math. It shoots groups in the .300's-.400's as it is, so it will be interesting to see what a seating depth change does, if anything.

 

[1000yardstare]

Typical of Rem centerfires in general. Have owned a 7600 .30-06, 7400 .308, SPS Varmint .308, 722 .308, 722 .222, SPS Varmint .223, VSSF .220 Swift and BDL 6mm Rem.

In all of these rifles lighter bullets would either not be in the case neck if seated .020 off the lands or only in by 1/16 inch.

I have always thought it was some sort of lawyer thing. Put in so much freebore that it would be difficult for reloads to blow them up. Doesn`t matter if some idiot accidentally loads with pistol powder. He will still sue the manufacturer.

But oddly enough seating light bullets with a lot of jump to the lands doesn`t seem to unduly affect their accuracy, in a hunting rifle anyway.

 

[jonbearman]

I have 3 700 vs's.Cant touch the lands ,so I jump them and they shoot fantastic.

 

[jhord]

Well the odd thing is I have another 700VS in .223, and the throat in that one seems short. I can seat any 40+ g bullet into the lands and still have plenty of bullet in the neck. It likes the bullets jammed .010", so if the throat in that one is shorter than it should be, I guess I lucked out! This .308" freaked me out a bit I suppose when I saw what the measurements are, but glad to hear it is normal.

 

[necchi]

Lot's of good advise about the SMK's being jump friendly, I like to keep enough in the neck to still keep runout at a minimum. I've got close too .215 in (not counting the boat tail) and all is well for a factory rifle.

 

[RonAKA]

I had figured on building up some loads with a .030" jump, but doing this would mean that only ~ .135" of the bullet's bearing surface would engage the case neck. That doesn't seem enough to me? What's the least I can get away with, any rule of thumb? I know "they say" you should seat it the bullet's diameter but that will be a huge jump in this rifle.

You should be able to get away with 0.100" in the neck (not counting any boat tail). I've gone as low as 0.070" in my 6BR, and still got pretty accurate loads. I only have about 0.001" neck tension, so I treat the loaded rounds carefully, and if needed can pull the bullets out by hand.

 

[jhord]

RonAKA, that's the info I'm looking for, thanks. I'm going to try .050" jump, which will be about 50% engagement of the neck on the bearing surface. (.155") If groups shrink I'll try .030" jump and then see what happens. I'll watch my runouts, and I usually start a round into the chamber with my finger instead of letting the bolt do it, so the bullet doesn't get knocked out of alignment. I am using a Lee neck collet die and it is putting about .0015-.0020" tension on the bullet with the rounds I have loaded so far.

 

[RonAKA]

No experience in a .308, but in the 6BR with 4-5 different bullets, they all have shot best with a .010" jam.

 

[jhord]

That's the way my 6BR is, too. Looks like I won't get to try it in this .308 but that's ok.