Savage 99 "walking" problem

[Maineboy]

I have two Savage 99s, one in 308 and one in 300 Savage. The 308 shoots fine-no problems with this gun using any load I've put through it so far. The 300 is a different story. When shooting 5 shot groups, the first 2 rounds will group near each other, the third will move in the 11:00 direction about 2 inches, the fourth will go the same way about two more inches and the fifth may be 6-7 inches from the first two, again at 11:00. It doesn't matter what load; cast or jacketed. Apparently the barrel getting warm is what does it. I'm wondering if removing the forearm would make a difference. I'm going to try that next time I take it to the range. Has anyone else had this problem? Both rifles have rotary magazines.

[atr]

I have a model 99C in .308 and it does the same thing but to a much lesser degree. I suspect the thin barrel may be a contributing factor. I also think that pressure on the forearm may also contribute. When I use the rifle for hunting I zero a cold barrel for one shot. I have not tried removing the forearm but I did make sure the forearm is firmly screwed to the barrel.
just my thoughts
atr

[Artful]

My 99 doesn't exhibit this - I'll be curious as to your result.

[MostlyLeverGuns]

Probably a forearm problem, though some powders seem to cause walking problems more than others. Things to check : Is forearm dovetail carrier centered under barrel? Is firearm screw 'too long' contacting barrel when tightened? Is forearm too tight against receiver? Try placing a couple shims cut from file cards in barrel channel in front of and behind forearm dovetail carrier - so forearm only contacts barrel right around forearm hanger at front of forearm. When benchresting on sand bags, place very rear of forearm on front bag very consistently ( mark with tape). Try starting with clean barrel, then with cold fouled barrel. The 'stick' powders (Varget, Rldr 15, 4064) seem to be more consistent going from cold to hot barrel for me.

[MostlyLeverGuns]

Another thing thing to check - is the stock bolt tight? Time, expansion and contraction of wood can cause the stock bolt to need tightening.

[pietro]

.


It sounds like the barrel with shifting POI could benefit from CRYO, a stress-relief process.

Most rifle barrels don't need it, but some can benefit from treatment.

http://www.300below.com/firearms-cryo-barrel/


.

[Maineboy]

Another thing thing to check - is the stock bolt tight? Time, expansion and contraction of wood can cause the stock bolt to need tightening.Hadn't thought about the stock bolt. I've done a lot with the forearm over the years except removing it. I've benched it off the receiver, front of the forearm, rear of the forearm, with me holding the forearm only; always the same results. Very slow fire, 4-5 minutes or more between shots, will produce good groups.

[Hardcast416taylor]

Light barrel heating up and `whipping`.Robert

[MtGun44]

Tighten stock bolt. Remove forearm and shoot a group HOLDING the barrel in your hand
and see if it still does it. Replace forearm if the walking is gone or reduced a lot, and see
if it comes back. If it does, look into what the Sav99 gurus have learned about the forend --
does it need to be attached to both bbl and action tightly (glass bed?) or to bbl and free
from action (?) or something different.

I would guess that there is a "known fix" for forend issues, but you need to diagnose it first.
Stock screw itself may fix it, or glass bedding the front of the stock to the action. I have a
Sav 99 in .300 Sav, but it does not do this particular trick.

Bill

[noisewaterphd]

A lot of good responses. I'd agree it is probably a result of the barrel heating up.

Best case, something is loose, or a pressure point is moving the POI as the barrel heats up.

Worst case, it's indicating a shot out barrel.

Good luck. The 99 is a great rifle, I hope yours has more life in it.

[M-Tecs]

Barrels don't walk due to being shot out. If the barrel is walking as it heats up this is cased by uneven stress in the barrel. It was that way since it was new.

[noisewaterphd]

Barrels don't walk due to being shot out. If the barrel is walking as it heats up this is cased by uneven stress in the barrel. It was that way since it was new.

I have seen many shot out barrels walk as they heat up, right before they turn to complete junk.

Cold bore will generally print maybe 3 shot groups, then it starts to walk. Sometimes predictably, sometimes not. Generally it starts mostly vertical, and then after a session or so more, you get the cone or spiral effect.

I have personally shot out a dozen or more overbore barrels, and witnessed it many times in our club.


I think a stress point is a more likely culprit, but it is not the only culprit IME. A quick inspection of the throat and crown could help put one's mind at ease.

[M-Tecs]

I have seen many shot out barrels walk as they heat up, right before they turn to complete junk.

I am a toolmaker by trade and I build NRA Service, Match and long range rifles on the side. I also do a few varmint rifles for friends. In total I have rebarreled about 200 rifles. I have yet to see one start walking due to a high round count. SS tends to hold it's accuracy well than if falls off quickly. 4140 barrels tend not to fall of the ledge as quick. In either material the first signs are loss of ability to hold elevation on the long range targets. Next the groups start larger. With some cartridges like the 6.5/284 1,500 to 2,000 rounds is max. With the 6mm BR's and 308's 3,500 to 6,000 rounds is normal. My primary prairie dog rifle is a 223 AR with a Krieger SS match barrel. It started life as a solid 3/8" MOA rifle. It currently has over 9,000 rounds of 40 grain Ballistic tips over 27.5 of H335 and it is still holding 3/4" MOA with zero POI issues.

I have installed two barrels that walked. The manufacture replaced them but I was out the labor for threading, chambering, crowning and polishing.

Not saying it can't happen I have just never seen it or heard of it from any of the match shooters or long range competitors.

What calibers, rifle types and round count have you observed walking with high round counts?

[noisewaterphd]

I am a toolmaker by trade and I build NRA Service, Match and long range rifles on the side. I also do a few varmint rifles for friends. In total I have rebarreled about 200 rifles. I have yet to see one start walking due to a high round count. SS tends to hold it's accuracy well than if falls off quickly. 4140 barrels tend not to fall of the ledge as quick. In either material the first signs are loss of ability to hold elevation on the long range targets. Next the groups start larger. With some cartridges like the 6.5/284 1,500 to 2,000 rounds is max. With the 6mm BR's and 308's 3,500 to 6,000 rounds is normal. My primary prairie dog rifle is a 223 AR with a Krieger SS match barrel. It started life as a solid 3/8" MOA rifle. It currently has over 9,000 rounds of 40 grain Ballistic tips over 27.5 of H335 and it is still holding 3/4" MOA with zero POI issues.

I have installed two barrels that walked. The manufacture replaced them but I was out the labor for threading, chambering, crowning and polishing.

Not saying it can't happen I have just never seen it or heard of it from any of the match shooters or long range competitors.

What calibers, rifle types and round count have you observed walking with high round counts?

I'm starting to think we are describing the exact same thing.

For me, it is usually 6.5, 7mm, and 30 cal that I wear out the most. I've shot out more stainless 6.5x284 than anything else.

[M-Tecs]

Normally when one refers to a barrel walking you are referring to a very predictable and consistence point of impact shift as the barrel heats up. This is primarily due to internal stress in the barrel but it can also be from stress points in bedding. I have very limited experience with bedding stress points since I normally fix any issues before testing.

With internal barrel stress the movement is consistent as the barrel heats up.

When a barrel is on the last of it's competitive accuracy life it will start to have elevation issues at longer ranges. Normally you do not see it at under 300 yards but it becomes noticeable on the 600 to 1,000 yard targets. This is not predictable or consistent.

If I own the barrel and it's caliber appropriate it gets turned into a prairie dog rifle until overall accuracy is gone or I start blowing to many bullets. For prairie dog rifles if it will no longer hold 1 1/4" MOA I consider it shot out.

[too many things]

there would not be any difference in thickness of barrel , both are 30 cal. I don't load 300sav were you using a hotter powder? and as said in early post it could be a heat treat problem with the barrel stock . It happens good example was the train rails when they first started the continuous rail. heat treat was a pass through deal and they had problem of keeping heat same on both sides . so the rails warped when the sun got very hot
try a slower powder

[noisewaterphd]

When a barrel is on the last of it's competitive accuracy life it will start to have elevation issues at longer ranges. Normally you do not see it at under 300 yards but it becomes noticeable on the 600 to 1,000 yard targets. This is not predictable or consistent.


That is where we disagree then. I have seen it be both predictable, and consistent. However, not in every case.

I concur 100% with everything else you have said.

[10x]

Shoot the gun without the fore end installed.

This is how I discover if a bullet walking problem in a Lee Enfield is from the fore end or something else

[northmn]

Had a 35 Marlin that did that. Removed the forearm and sanded it out as it was very tight. Mine was every shot to the right. It got consistant enough to hunt with after losening things up. For a hunting rifle I only worry about 3 shot groups anyway.

DP