Long throat and bullet seating

[Bart B.]

Unclenick:

Another helpful strategy is to neck size-only so the fireformed cartridge case centers itself in the chamber. If you leave the last little bit of the neck unsized just ahead of the shoulder, that will center the bullet in the neck portion of the chamber.

Not so in my experience and actual measurements.

Full length sized cases that headspace on their shoulders center just as perfectly as neck only sized ones. And both versions end up with the necks free floating in the chamber unsupported by no part of the chamber neck whatsoever. That unsized portion of the case neck is still smaller than the chamber neck's diameter at that point; not by much, but measurable.

Both types' shoulders are what centers them in the chamber from firing pin forces when fired or in-line ejector forces before firing. They fit in the angle matching chamber shoulder perfectly centered there just like one Dixie cup placed in another. Even a .243 Win. round's neck and bullet will center perfectly in a .308 Win. chamber 'cause their shoulders have the same dimensions and angle.

And both type's bodies are clear of the chamber walls all the way around because they're smaller in diameter. . .with the exception of the case body at the pressure ring pressed against the chamber wall by the extractor on the bolt head opposite that point. So the back end of the case is off center in the chamber by .001" or a tiny bit more.

 

[cw308]

I have a Rem.700 LTR 20" brl. 308 cal. 1-12 twist rate also have a long throat, the Varment is the same as the 700P 1-12 twist only comes with a HS Presion stock. Black Hills match ammo will be accurate with a long or short throat. Don't worry about the jump, I also roll my own, so try different powders, Varget - IMR 4064 - RL 15 all work great in the 308 cal. In my 700 I stuck with 2.800 OAL. 168 gr. Sierra HPBT. Tried full, neck & parcial neck sizing. What works very good in my 700 is 2.800 OAL 168 gr. Sierra HPBT, IMR 4064 42.0 gr. I never load hot, ranges on LI NY are max 200 yards, at 200 group size 1/2 - 3/4 with everything Remington except a Jewell trigger. 1/12 twist rate is perfect for a 308 Cal. as long as your not shooting 180 gr. bullets. Find the right combo and your 700 Varment 308 Cal 1-12 twist with a 26" brl. will be a Tack Driver. Good Luck with your rifle, BE Safe Chris

 

[Bart B.]

cw, people have won matches and set records shooting 180 and 190 grain bullets from 1:12 twist 308 Win barrels. Western Cartridge Company loaded 197 and 200 grain bullets in .308 Win match ammo for Win 70 target rifles' 1:12 twist barrels. I've shot all of these combinations and they're very accurate.

 

[cw308]

Bart B, I agree. What do you feel is the ideal bullet weight for a 308 out to 500 yds. max

 

[Bart B.]

It depends on what you want the bullet to do when it gets to 500 yards.

If you want them to all land closest together for best accuracy on paper as well as have minimum recoil so they're easy to shoot straight, 155-gr. Sierra Palma bullets would be my choice. They'll stabilize well from a 1:12 twist barrel of short to medium length.

If you want them to drop game, then a 165- to 180-gr. hunting bullet of your choice would be my pick. While their heavier recoil while the bullet's going through the barrel is more than the 155's, they're more suitable for taking big game at that range.

 

[10 Spot Terminator]

Long throats and Remington model 700s' seem to be the norm . I bought a new CDL in .243 thinking it would be a great varmit rifle to better buck the wind than my Tikka .223 . This wasnt the case insofar as loading accurate bullets under 87 grs. and preferred the 95 gr. and heavier persuasions . It had a setback of .125 off of the lands using the Noslet 95 gr. Combined Technology bullets that would shoot 1/2 in. groups @ 100 yds. under a moderate load of H414 . This was the only load I was able to develope that was consistant in its grouping with bullets under 100 grs. and ended up selling it to an antelope hunter . Accurate loads in long throated bores in any calibre in my expierience have been hard but not impossible to obtain and have given additional cause to my purchasing the Stoney Point ( Hornady ) COAL comparator tool . When I am shopping for a new or used rifle I carry this tool with me as well as a set of good calipers and a good sample of bullets I intend to use. On the bullets I have the ogives clearly marked with a sharpie as well as the measure from the base of the bullet to the ogive and the oal of the bullet . If the dealer isnt willing to let me measure the freebore ( this has only happened once ) I politely thank him for letting me view his firearm and let him know I will be buying elsewhere . While at it if possible I measue the inside lenghth of the magazine as well . I have seen weapons in a given calibre have shorter than normal magazines where being limited on COAL by the magazine length creates a bullet seating/accuracy conundrum as well .

10 Spot

 

[cw308]

As always, Thanks for the good info. I will give the 155 gr. sierra palma a go. I only target shoot max. 200 yards