Consistent alternative when lands too far to jam?

[CardiacKid]

I posted this over in TresMon's section 3 on determining OALs, but figured I'd ask it out here to get some answers from other experienced loaders that have already read through those posts.

I'm with the other .308 700P guys that have an insane amount of excess in everything in my chamber - actually sent TresMons a couple of PMs about how over some of my measurements were to confirm with him, as this is my first bolt action rifle and first go around with precision loads.

Here's some of the specs in my Rem 700P in .308:
Headspace/Shoulder Length: 1.564"
Chamber Length: 2.055"

When I use the Hornady OAL Gauge and Comparator, here's some of the ridiculous dimensions I get using their case and a 168 SMK:
COAL: 2.927"
Base to Ogive: 2.363"
If I were to seat bullets to those spec (and obviously they wouldn't fit the magazine in my AICS) I would have such a ridiculously small amount of bullet contact to neck that it doesn't even sound possible. Just as a quick reference, the base of the bullet would be just about flush with where the case neck changes its angle to the shoulder, meaning about half of the case neck would have contact and the other half would be the boat tail.

I spent hours going over and over with the Hornady OAL gauge, jamming rounds and trying the "cut slots in the case neck for tension" and jam it method. I even used a piece of folded paper to move the plastic rod on the OAL gauge to make sure I wasn't using caveman strength with it and jamming the round, but to no avail. The only spot I get a definitive "stop" where the ogive meets the throat is wayyyy out there at the 2.363" length.

Well after more searching on this site and others, I'm finding that these chamber tolerances are pretty common for the 700P and similar models. In other words, touching the lands really isn't feasible given the very little amount of bearing surface I'd have on the case neck - at least that's what many others have decided as well.

Is there a viable alternative to maintain a level of consistency? My thought process is first to look at COAL to determine the max length I could feed in my mags (looks like 2.810 should be in the ball park, and again - to even reach the lands I'd be loading around 2.937).
From here, could I seat using consistent ogive depth as the common denominator? IE, COAL is going to hover in the sub 2.810" range but ogive depth will be consistently 2.XXX. Anyone have experience with this? I guess the only refinement after this would be to see if I'm shooting tighter with varying ogive lengths, and thus jump lengths since I can never safely jam and then work toward jump. Thanks

 

[Skg_Mre_Lght]

Re: Consistent alternative when lands too far to jam?

The short answer is to find a good load and forget about COAL, just make sure it fits in the magazine. I do this with all of my factory barreled rifles, and screwing with the "jump" is my last bit of tweaking when it comes to my long range rigs and my varmint rifles.

 

[gcoulsey]

Re: Consistent alternative when lands too far to jam?

if the 168 smk is what your planning on shooting, forget about getting close to the lands, they shoot fine with a jump,
same is true for the 175 smk's.

start at mag length, and you will be fine

 

[MinorDamage]

Re: Consistent alternative when lands too far to jam?

gfunk is correct. Most bullets with tangent ogives are jump tolerant. VLDs tend to be quite a bit more finicky. SMKs, AMAX, and some of Lapua and Berger's non VLDs will do fine.

Josh

 

[jbailey]

Re: Consistent alternative when lands too far to jam?

Why exactly do you want to be in the lands? Jamming it in the lands is not a path to consistency, because the distance to the lands continually changes - it gets longer. Unless you think there is some accuracy reason to be in the lands for a really finky bullet design, there is no reason to jam bullets. Plus a jumped bullet is a safe round to unload unfired - no risk of powder spillage.

If you are worried about getting VLDs to shoot in this chamber, give this article from Berger a read: http://02b0516.netsolhost.com/blog1/?m=200904

 

[CardiacKid]

Re: Consistent alternative when lands too far to jam?

I had a box of 168 SMKs to screw around with for my first couple of reloads. I have since switched to the 175gr SMK after reading all of the information about the increased performance past 600 (600-800 is my goal right now). Loading to mag length definitely makes things a little easier with the handloads - don't even bother with trying to set a consistent seating depth by ogive then? Just COAL at mag length and off to the range?

 

[CardiacKid]

Re: Consistent alternative when lands too far to jam?

only reason for jamming was to start my load development from there as the process in TresMon's threads described.

 

[gcoulsey]

Re: Consistent alternative when lands too far to jam?

measuring off the ogive is better,
to keep things simple, load a round up to your desired COAL,
(2.810 or whatever)
take your ogive measurement from that round, and make all the rest the same, using that ogive measurement.

job done

 

[holdoff]

Re: Consistent alternative when lands too far to jam?

You could also try a different bullet. When I tried 155gr weight projectiles I quickly discovered that I couldn't reach the lands (REM 700 PSS). Until I saw some pictures of various projectiles side by side (accurate shooter.com 308 load guide). Switched to the Lapua 155 and due to it's length, was able to play with seating depth. Funny thing though my best loads were mag length.

Anyway if you want to single load the heavies will easily reach the lands and of course loading out that far will allow slightly larger powder capacity for a given load.

 

[LoneWolfUSMC]

Re: Consistent alternative when lands too far to jam?

If you shoot a factory Remington, load them to fit the mag and drive on.

I don't jam the lands on any of my rifles. The only reason for me to load long on the .308 is to get more powder capacity with really long bullets (208 AMAX).

Here is another tip. Set your seating die, then leave it alone. Don't try to measure the COL of each round. If you don't have a comparator it's going to screw you up and even if you do have a method to measure off the ogive you rifle is more than likely not accurate enough to see the minute difference. Measuring off the meplat with a caliper is NOT accurate at all.