Rem 700 308 keyholing at 100 yards......help!

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cttbax

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Hey folks,

I picked up a new in box Rem 700 SPS in 308 with 20" Barrel. I had the barrel threaded at ADCO (reputable gunsmith). Today I took it to the range for the first time, and I had a pretty bad day on the range. I only fired 15 rounds total. I had six different variants of handloads, bullet weights ranged from 168 to 180 grains. Bullets are all what I consider high end e.g. Hornady A-Max, Sierra Match King HPBT. I also shot some 168 grain military ball ammo, not sure what the specs are on that ammo. But every shot was erratically high, extremely left or right and the bullet were keyholing... as in entering the target sideways. It seems that this barrel is not stabilizing the bullets at all.

So most of the folks at the range were quick to blame the threading job. The barrel was not cut in length, meaning it was not cut from 24 to 20 inches or anything. The crown is visible, and there are no dings or strikes on the crown. Looking down the bore, I see no issues with the rifling, I cleaned the gun thoroughly before I took it to the range.

According to the Remington website the SPS model is a 1 in 10 twist...and from everything I know.. that should stabilize 168 and 180 grain bullets easily. So I am puzzled. All of my loads are published by the powder manufacturer, I was pushing max loads of Varget, Benchmark and H335. OAL was 2.80 on all loads.

Any ideas fellas? I am scratching my head on this one. What would keep this 20'' 1 in 10 twist barrel from stabilizing bullets that are well within the weight range for this twist rate?
 
i'd check to make sure it's actually 1-10 as advertised. (run a cleaning rod with a tight patch down and put a piece of tape on the rod. measure with a ruler how far you have to push the rod in for the tape to make one revolution.)

i can't imagine how threading would change that, since that's entirely external.

starting with max loads is always a bad idea, but i'm sure you know that and are just taunting fate, eh?

do you have access to a chronograph by any chance?

when you shot, did the recoil feel normal?
 
Max advertised or published loads... yeah kinda risky..
no chronograph, although I have been looking for an excuse to buy one.
Recoil felt normal....
 
It may be the boattail bullets. Were they all boattail bullets ? .
If they were, try some flatbase bullets and report back.
 
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Amax and Match kings are boat tails, not sure on the military ammo i shot...... I thought boattail would HELP stabilize when it exits the muzzle.
 
If you can verify that the flatbase bullets shoot o.k., then I'll write the explanation
to this up, it's lengthy. Use any flatbase even the Rem . core locks are o.k..
 
for a given weight, boattails are more difficult to stabilize because they are longer.
they reduce drag though, and give a higher BC
 
wow, is it that off-center in person? or just looks off-center in the photos?
 
Ya, I was hoping it's just the photo, as the crown looks even.

I suggest some flat base 150gr at a medium power powder charge to see if that solves the problem.



NCsmitty
 
Well.... Sad part is that you didn't fire the gun before the threading job. If it were bad then, you could have sent it back to Remington on their dime. Now.... :uhoh:
Not said to beat up on you, but someone else may benefit. Good luck in sorting this out.
 
When you test fire it again, put some white-out (the stuff that erases typing errors) on the crown and observe the starburst pattern after each shot. It will become evident
quickly if there is a crown problem. If it is a problem with the boattail bullets, you will notice a difference right away with the flat base. This problem crops up from time to time in new rifles ( all brands , some a bit more than others ). Let's see what happens.

I believe those Federal Gold Medals use a Sierra boattail bullet, and we don't want to use those here.
 
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No need for the whiteout. There should be a pattern on the end of the crown that should be visible after 10 or 15 rounds. Standard threading of a barrel would include putting a center into the end of the barrel. This will most definately make it necessay to recrown the barrel. If it was recrowned it may need to be recut again.
 
Try a box of factory ammo, either Winchester or Remington or Federal. If it still keyholes it's your gun, either the mods or from the factory.

If it shoots decent groups it's your reloads for unknown reasons.

I can't see how any action/stock interface would cause keyholing. Stringing or wide, erratic groups mayby, but not keyholing.

I'd almost bet the centering tool suggestion is the cause of your problems and barrel may need to be recut.
 
I'm not an expert but from looking at the threads, receiver end, with a tapper that deep and the space it will leave between the brake/suppresor and the barrel. I would think that you are getting some wicked flex/whip, real bad harmonics ????.
 
That is very unusual. One possibility is that the scope is simply sighted way too high and the bullets are bouncing off the ground before striking the target. If you were shooting in a rifle tube or indoor range, this is particularly likely. Have the gun bore-sighted or try shooting at 25 yards and see where you are on paper.
 
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