Savage 14 AC 7-08 major accuracy issues...help

[keeki]

But the keyholing isnt gonna be caused by a scope or base. Thats the bullet not stabilizing. Take your cleaning rod with a swab and run it down the barrel and measure the twist rate. Measure how far it travels to make one revolution. Im betting its an 11 twist.

[sav101]

The swab down the barrel is telling me it has an 11"twist rate.

So, if this is the case what grain ammo is this going to shoot accurately?

[barrel-nut]

Bingo!

[keeki]

change the barrel to a 9.5 twist, go down to a 120gr bullet, or send it back to savage to get the right one.

[possible]

Call savage and arrange to a rifle with the appropiate twist shipped.

[sav101]

I am definitely contacting Savage tomorrow.

I did the swab in the barrel about 20 times and it is an 11" twist. I think I even called about this back in March before I bought it because they list 2 different 7-08's on the savage website with diff sku #'s.

Thanks for the help on this, you all definitely know your stuff.

[LHitchcox]

Swap the scopes and use the known good scope and see what it does. Many possibilities covered already. I have an 11FL that drove me nuts. Four inch groups with handloads that shot an inch and a quarter in a handi rifle. I shortened the base screws and action screws, floated the barrel, changed scopes, inspected the crown, etc. Turns out that my problem was the bolt handle cut-out was off. The stock started out as a right hand stock and they filled the original slot and cut a new one on the left side. Unfortunately, it was almost a quarter inch too far back. The bolt handle was binding against the front of the cut out. I found it only because my buddy put a rattle can paint job on the stock and I finally noticed the paint was rubbed off at the cut-out. I filed out the slot and that dog became a .75 shooter.

[cmorsch]

You may also want to try a slower moving projectile. It helped my with my 30-06. I slowed the bullet down a few hundred FPS and my groups tightened up 3-4 times. Its now shooting .345" groups at 100 yards for me.

[keeki]

If the twist being too slow is the problem, I think slowing the velocity down would only make it worse.

I think. ???

[sav101]

I called Savage 10 minutes ago and explained the situation, gave them the serial number, etc... The service rep said my options were to send it in and they will look it over and see why it is inaccurate and fix any problems, and they would send a target with the ammunition they used to test fire it. I asked if he could tell me the twist rate and guess what, it has an 11-1/2" rate of twist. They said the gun was made in 2010 and probably in the (Davidson's)warehouse for a while and since it was sold to them and resold to me they couldnt do a rebarrel under warranty.

So then I called Davidsons and asked if they could tell me the rate of twist on the gun. 1 in 9-1/2" twist. Wrong. Davidsons is manning up, taking the gun back, having Savage re-barrel it to 1 in 9-1/2 and shipping it back. I'm figuring I'll have it back by next deer season. Anyway Im happy with the outcome, could've been worse.

[barrel-nut]

I'd at least try a few 120's before you send it back.

[barrel-nut]

If the twist being too slow is the problem, I think slowing the velocity down would only make it worse.

I think. ???


+1

[cmorsch]

Faster twist for heavier bullet. the heavier you go the slower. so slow down a lighter bullet to achieve the speed of the heavy one. There is a table on http://www.riflebarrels.com/products/caliber_twist_rates.htm that may help.

[keeki]

to stabilize a long bullet, it has to turn at a higher rpm than a short bullet. the faster it is moving, the higher the rpm.

[cmorsch]

He might be shooting to light of a round in to fast of a twist

[barrel-nut]

Faster twist for heavier bullet. the heavier you go the slower. so slow down a lighter bullet to achieve the speed of the heavy one. .


Cmorsch, with all due respect, I think your logic is faulty here. Bullet stability is a complicated product of bullet diameter, length, speed, and rate of rotation. You are changing two variables - speed, and length of bullet (lighter). Any gains in stability in this case will be due to using a shorter projectile, not from SLOWING DOWN a shorter projectile. In other words, slowing down a shorter bullet just for the sake of matching the velocity of a longer bullet, is not going to make the shorter bullet more stable in flight.
Over-rotation of any bullet (too much velocity for a given twist) can make it slightly less accurate than if it was within its optimum RPM's, and in extreme cases can actually make the bullet disintegrate in flight, but it will remain stable (spinning on its axis) up to that point.
The problem the OP is having is on the opposite end of this spectrum. Keep in mind that bullet stability and accuracy are separate issues. Stability can and does ultimately affect accuracy, but there are a host of other factors that affect accuracy. Stability is required for the bullet to remain spinning on its axis, or else it begins to tumble in flight. Slowing a given bullet down if it is already on the verge of instability, will only make the condition worse, resulting in key holing and very poor grouping, which are problems the OP is already having.
Shooting a shorter, lighter bullet at HIGHER velocity, such as a 120 gr in this case, should improve stability, and accuracy in this case, and is something that has been mentioned many times throughout the course of this post. Apparently the OP does not want to do this, as he has not responded to these suggestions yet. That is understandable if he only wants to use 140gr bullets, but the only thing that would help in that case would be to push them faster, which would require handloading, and may push the envelope of safety pressure-wise.

[keeki]

+1

[sav101]

Barrel-nut I am following what you're saying. I didn't plan on using any ammo lighter than the 140 range, I want the gun for deer hunting and at a range no greater than 150-200 yards, most shots I take are between 50-85 yards and rarely a long shot on an exceptional animal(big buck).

My long time deer rifle is a Remington 7600 308, a pump action by the way. I use 150 grain Remington Core-Lokt off the shelf ammunition. Before that I used a Rem 760 in 30-06, again 150 grain ammo nearly identical performance, the later rifle was retired after three generations hunted with it. So 140 is as low as I want to go, I could use less since I hunt over farmland and not woods, I agree it's worth looking into but I want to stick with what works for me. I know what the 308/30-06 150 is capable of and the ballistics are similar to 7-08 140's so thats where I want to stay.

I did use Hornady Superformance GMX 139 Gr which have a velocity of 2910fps, about 110 fps faster than the Winchester 140 Gr Ballistic Silvertip, and the groups were larger than any other slower ammo and the bullets were key-holing the target.

I was wondering if a BoatTail bullet would make a difference in accuracy in the 1 in 11.5" barrel.

[keeki]

the boattail is longer which requires more twist. The longer the bullet the more the twist, so you could probably stabilize a 140gr round nose, but who wants to do that

[sav101]

I appreciate the advise as far as hands loads and lower grain bullets and for some it works fine. I dont load or reload rifle ammo but I can understand and benefit of creating custom loads for ones gun and the satisfaction of making the optimal round for your gun. At one time I loaded shotgun shells when I was skeet and trap shooting and I developed my own load for each that I was quite proud of. So for those that offered their advice in that regard I thank you but I am currently limited to what the store shelf has in stock.

I am hoping that the problem will be resolved when the 1 in 9.5" twist barrel is put on the gun.