Gunsmithing Savage 7mm Problems with pics - Help!

[mram10]

Went and shot my friend's savage 7mm and the first 2 shots grouped well, but the third would always fly. I thought of scope bases, rings and scope at first. Took off old and put on new EGW tac base and Warne rings. I switched scopes and it still shot the same. I re-bedded the front lug area of rifle and extended it to 1 1/2" forward for recoil lug. Checked action screws and made sure they were torqued correctly. Shot reloads and factory ammo. Here are the results AFTER all of that.

Harris swivel bipod, 100yds, factory ammo x 2

Different Harris bipod, factory ammo

Off front rest, factory ammo no muzzle brake

Could it be barrel heating problems??
Muzzle brake doesn't seem to make sense that it works for 2 but not all three.
Thanks guys.

 

[trailrider121]

Re: Savage 7mm Problems with pics - Help!

Are you waiting between shoots? How long? Is the rear tang floated? What are the action screws torque to? Savages even in their cheap plastic stocks will shoot well.

 

[ar15is223]

Re: Savage 7mm Problems with pics - Help!

I have a few questions.Could you post a couple pictures of the rifle. Also how is the muzzle brake attached?

 

[mram10]

Re: Savage 7mm Problems with pics - Help!

I shot three in succession. About 10 seconds apart. The rear tang is bedded. Action screws are torques to hand tight with my allan wrench

No torque wrench used. It use to shoot great. I sold it to him and a year later he said he hadn't shot it much and it just wouldn't shoot. I can't figure it out.

I will take the gun apart and take pics of everything. MB is threaded on and screwed on hand tight. It doesn't loosen while shooting.

 

[ar15is223]

Re: Savage 7mm Problems with pics - Help!

Thats tough. The spread on the second group must be around 6". I don't think that the torque on the action screws could even cause that much of a spread. Have you checked that the barrel nut and barrel are still tight?

 

[mram10]

Re: Savage 7mm Problems with pics - Help!

Here are pics of the bedding job, rings, etc.

 

[jasonZ]

Re: Savage 7mm Problems with pics - Help!

Try playing with action screw torque. Best to have a torque wrench though. There's an article about it if you search (not necessarily on the hide). Also savage likes the rear tang floated. I never bed the rear tang, but that's me. Check the barrel for "free float". 3 shots from cold bore shouldn't be enough to cause heat problems even with a shorter and fairly rapid fire. Now several groups quickly, yes. Does the bolt cycle smoothly or does it bind? I'd (now this is just me) float the rear tang and play with the torque. You may not have to tight enough even. I'd first make sure your barrel is free floating. I don't even bed the barrel nut, but again that's just me.
Good luck, Jason

 

[BenY 2013]

Re: Savage 7mm Problems with pics - Help!

If the rear tang is bedded, I think you should free float it. My Savage .308 shot like crap until I floated the rear tang. Also be sure that the barrel is floated. Savages are a bit picky about that rear tang.

 

[mram10]

Re: Savage 7mm Problems with pics - Help!

I sanded down the rear tang area to float it. I also milled out the bedding forward of the lug. Back out to the garage for a new bedding job. I'll scuff it up, acetone it, redo the bedding, duracoat and call it good. I'll even get out the torque wrench to make sure it is perfect. It better shoot this time!!

Thanks for the help guys. I will keep you posted.

 

[mram10]

Re: Savage 7mm Problems with pics - Help!

Still did the same thing! We then took out his savage 111 270wsm and it shot worse as it got hotter. Shots were all over the place. Again, off a bipod and rear bag. All shots were at 200yds with very light winds. No excuses to be making such crappy groups .... after the first two shots.

Could the threading on the muzzle brake cause this?? Since the barrel and the brake won't expand at the same rate can that cause problems?

 

[UNCIVILIZED]

Re: Savage 7mm Problems with pics - Help!

Is this factory ammo new, off the shelf, or stuff that's been stored @ home for a while? If it's the latter how has it been stored? IE; if it was badly stored then that could account for the crap groups.
I've worked with some where when you fired it, the shot variances sounded like an out of tune piano in a cartoon.
Just a thought/something to consider. So it might be worth buying some ammo from a couple of different places just to play it safe.

Also, is it possible that one of the screws on the base is touching the bolt? I'm not familiar with Savages, but know that such is possible on some rifles. And that would surely muck up your accuracy as well.

That & might the magazine box be binding up against the stock in a way which could affect things? You could try removing the mag box, & single feeding the rounds to see.

I don't suppose your friend took off the barrel, & now the headspace is different? If you don't mind going to "page 0", you could pull the barrel, reset the headspacing with a set of gauges, & start over. And while you're at it, take a magnifying glass & have a good look at the crown.

As to your question about the muzzle brake being a possible cause, it's possible. I'm not sure when it was put on, or how competent the smith was, but minute crushing of the bore is possible if threads aren't cut properly. Also, if they weren't cut right, like say a bit too shallow, then when you put the brake on it'll alter the muzzle diameter & shape minutely.

 

[BoilerUP]

Re: Savage 7mm Problems with pics - Help!

Did you again fire 3 shots 10 seconds apart? If so, I'd wait a minute between shots with the bolt open and let us know what you experience.

Do you have a different stock to try the barreled action in?

 

[mram10]

Re: Savage 7mm Problems with pics - Help!

Ammo was two types brand new from store the last time.

The screws don't bind the bolt, but I will check to make sure it isn't touching.

I have 7 rifles done with muzzle brakes from the same smith and they all shoot great. They all have thicker contours than that thin savage though.

I haven't tried without the magazine box. I will try it. Also, have not tried it with a different stock.

 

[mram10]

Re: Savage 7mm Problems with pics - Help!

BoilerUp,
I haven't tried another stock, but can.
The shots were 5 shots, about 5 minutes apart. First two shots were close. Every other shot varied. Even tried different scopes and brand new base.

haven't messed with the barrel. I will before I rebarrel. I might just trade him something else and put a heavy barrel in a 30 8mm. Been wanting one for a while anyway

 

[pyplynr]

Re: Savage 7mm Problems with pics - Help!

Have you checked the barrel crown. Might have a lil nick in it or something.

 

[my human host]

Re: Savage 7mm Problems with pics - Help!

I would get rid of the bedding under the barrel and nut if you haven't already.

If indeed the first 2 shot are always good and the 3rd goes wild, you most likely have erratic contact between the stock and barrel or your barrel bedding is putting significant pressure on the tube.

I've seen rifles with less than perfect action bedding shoot reasonably well, but the minute you make the barrel part of the bedding you need perfection from front to back.

My assumptions are based on your statement that this rifle is a proven performer.

 

[my human host]

Re: Savage 7mm Problems with pics - Help!

Also, make sure you've removed any bedding compound that may have leaked into the action screw holes in the stock. Good luck.

 

[mram10]

Re: Savage 7mm Problems with pics - Help!

Thanks guys. I rebedded the thing already. I made sure to float the rear tang, drill out the action screw holes and taped off the barrel nut and barrel to avoid excess contact. I think I will go from square one and remove the barrel and recrown. I didn't recrown because the first two shot were solid, and it doesn't make sense to me the crown would cause this problem. Can't hurt though.

I will try my other savage stock to see if that somehow helps.

 

[jasonZ]

Re: Savage 7mm Problems with pics - Help!

I can't really tell from the pics, but is it a sporter barrel? I had a factory savage 7mag and I had a similar problem. The tuperware stock flexes a lot and I ditched it for a boyds and pillar bedded. That took care of the issues, unless I fired rounds multiple times in rapid succession. I could do 3 pretty quickly from cold bore, but after that ya never could tell what it would do.

In this case I'd definitely wonder if you had barrel contact somewhere, especially under load of the bipod if the stock was flexing. It was a good choice to float the tang. I've never read anything that recommended the tang be bedded. Also I would really recommend finding that article about action screw torquing. They talk about playing with action torque for optimum accuracy. This was done at the range with actual shooting at different torque values. It seemed that the front and rear were actually torqued to different values with a torque wrench and they found optimum accuracy. I think the front was torqued more than the rear with that particular rifle. Headspace could make a difference and also have you thought that the barrel is shot out.

 

[woodman0663]

Re: Savage 7mm Problems with pics - Help!

It is kind of hard to tell from the pictures, but is the objective bell touching the rail. Also, looks like may be the power ring is touching the rail. If either one of these is happening, the I would try higher rings.