remington 7400

yes a friend has a remington 7400 in a 30-06, he's trying to sight it in with remington 180 grn corelokt's,On paper it show's the bullit tumbling,any reason's why

wow this shouldn't be happening, try another brand ammo @ 50 yards. 150 grain

Check for an obstruction in the barrel.

Check the crown for damage as well, something isn't right.

I've seen screws used that were too long for barrel thickness when mounting sights/scope mounts that went into the barrel.

Possibly a rusted out barrel?

Corelokts...

Too heavy of a bullet. I think those 7400 at like a 1:14 twist with a 20" barrel. Drop down to 165gr or less. I have one and that fixed the same issue your friend is having.

Not sure if it's the same issue, but I have a 742 and it doesn't really do well with anything over 150 gr ammo.

Why would the 180GR be too heavy for his 30-06?

Yep same issue. Mine is a 742 as well. Have shot several different weights and got huge spreads and some key holing wioth the heavy
mainly the 180gr. 155gr shoot the best in mine. noticed the same in my buddys 308. it don't like heavys.

It's a function of matching the barrel's twist rate to the weight (and length) of the bullet. A 1:14 twist means that there is one full rotation of the rifling every 14 inches. The longer/heavier the bullet, the faster the twist rate needs to be to properly stabilize the bullet. 1:14 is pretty slow for a .30 caliber bullet, meaning it will probably shoot lighter/shorter bullets better. That's why people are suggesting a 150 - 165 gr bullet.

We need a sticky explaining twist rates and bullet weights. Maybe include a chart of popular calibers and what constitutes a fast twist and a slow twist in each along with recommended bullet weights? JG, Chad, one of you smart guys up to that?

Ive always wanted one of those rifles in 3006 or 270.

Here's a few numbers I cruched real quick. Since we are shooting the highest of quality Rem Core Lokt ammo (cough cough), Rem shows a velocity of 2700 fps, which I'm going to assume is figured from a 22" barrel. The 7400 model shows an 18.5" barrel, so you will lose about 90 fps from a 22" barrel. Now this is a semi auto, so some gas energy will be needed to cycle the action. Most AR-10's lose 100 fps for this, which would be about right for this rifle also. 2700 fps minus the 90 fps for shorter barrel and 100 fps for cycling puts you about 2510 fps in this rifle.

Now, Core Lokt run a flat base bullet and it is a soft point. I don't specifically know the exact bullet length of this bullet, but I can certainly get very close. The Hornady 180 SP flat base is 1.236" long and the Sierra SP Pro Hunter is 1.220", I'll use the longer bullet of 1.236" for my calculations. And remember, bullet stability is based off of bullet length, not the weight. Naturally, the heavier a bullet is, the longer it is (generally). But if you compare stability factor of a 180 grain SP flat base to a 180 grain boat tail HP (BTHP) match bullet, the stability is totally different in a given twist rate. (It's the exact same reason I use flat base soft point bullets in my SUBSONIC ammo, instead of BTHP match bullet- the flat base shoot better and are more stable)

So, the velocity should be 2510 fps, with a 180 grain bullet that has a length of 1.236" long, and let's say that the rifle has a slow 1:14" twist. The bullet stability factor is a 1.30, which is still adequately stable (anything over a 1.0 is stable). It's on the lower side, but it should easily be stable. Even if we went with a longer 180 grain bullet, like a boat tail, the length would be about 1.280", and this puts stability factor at 1.14, which is still stable.

If the rifle has a 1:10" twist, stability factors are 2.0+ on ALL 180 grain bullets. So, if the rifle is a 1:10" twist shooting 180 grain, and the bullets are tumbling, something is really wrong. Honestly, even a 1:14" twist, bullets should be stable. So, what's causing this, I have no clue. But something is jacked up.

Crappy target paper !!!

Your friend only said "on paper it appears to be tumbling"... I have a 742 and a 760, to my knowledge I have never had a tumbling problem. But I do know some paper isn't any good for target use---it tears funny. I have shot ammo from 125-220 gr, commercial and handloads, and never seen any sign of tumbling, on paper or game.

Before I started rebuilding the gun or buying more ammo, I might use another type of target with another type of backing (cardboard, styrofoam, wood paneling, ect). KISS

make sure it's absolutely clean, bore and gas system.
a relative once tried those Remington accelerator sabot
rounds through a 742 and ended up locking it up tight-tight-tight.
those guns weren't made for running any plastic through.
when I bought this last 7400 .308, I ended up having to clean
it out with a whole bag of patches and most of a bottle of solvent
to get the black crud out. it shoots like a new one now.
I suspect the previous owner couldn't get it to cycle properly
and sold it to me.
I'd clean it good first and see what happens. it will need
cleaning eventually anyway, and won't cost anything to try.
good luck

I guess Mikeydon disappeared

I just cleaned and sighted in my financial guys in .243

wouldn't own one if you gave it to me

shot okay with a POS Bushnell on it

My 742 is the same way.