Inaccurate Ruger M77 (the original one) 7mm Mauser

[41magsnub]

I have an older Ruger M77 7mm Mauser shooting new factory federal 140 grain bullets that at 100 yards had a group (use that term loosely) of about 6" which is pretty sad. I was shooting from a bench rest and not 30 minutes before using my 22-250 did 2" groups at 250 yards. The day was absolutely calm so no wind to skew things. I had somebody else shoot the gun to make sure it was not me and he had similar results.

The gun itself while old has not had that many rounds through it. If I had to guess it would be under 2000, basically nothing that should have worn out the barrel or anything. My Dad bought it new for hunting when I was a kid and gave it to me when he quit hunting several years ago to replace my .243.

The scope on the rifle is the original scope bought at the same time. It is a Tasco something or other. It is pretty worn and I can't read the model but it seems to be a pretty basic 3X9.

What do you guys think my problem is here? Is it the scope or is it possible that there is something wrong with the gun?

Thanks for any input!

 

[dakotasin]

start w/ the easy stuff first. what kind of shape are the mounts in? rings/bases tight?

next, adjust the pressure on the bedding screw - it can make a huge difference.

next, test the scope - rather, replace it w/ one of a known quantity and make sure the scope is good.

what kind of shape is the crown in? re-crown it - it probably is in need of a little touch up there.

 

[41magsnub]

Thanks for the input. I put a screw driver on everything I could find on the gun at the range after the first 3 rounds we so off. Forgive me though, I am a bit of a noob. What do you mean by crown? Or is that one of those things if I don't know it I should be talking to a gunsmith?

Edit: never mind, I do know what that is. I just need another drink or something. It is the barrel opening.

The other thing I am thinking is the scope is pretty old and I would like something a little better. I should go buy a scope, if I come to find out the gun is screwed and I get a new one I'd be wanting to buy a scope anyway.

 

[asknight]

Has the bore ever been cleaned, really cleaned?

 

[rangerruck]

I would start off with a foaming cleaner, and do the process at least 3 times. let it sit in for 15 mins. then brush it a couple of times, then patch it out. repeat at least twice. Secondly, lets divide, gun/scope. take off the scope, and shoot it , open sites, at 50 yards. this will tell you where the problem lies.

 

[Dithsoer]

Several things could be contributing to your inaccuracy:
1. Look at the crown (muzzle). Does it look dinged up? Dented? Burred? If the damage is minor it can be remedied at home with very fine sand paper. Round one end of a dowel rod a little larger than the bore, lay a piece of sand paper (crocus cloth is better) over the muzzle and press down while turning on the dowel, the point being to smooth out the imperfections.
2. Where are the shots going? Lateral stringing suggest loose scope mounts, action screws or pressure variances in the ammunition ( old ammunition, ammunition that has been exposed to excessive heat, inept reloading, etc.)
3. Older Tasco scopes were of a lesser quality than the ones the company is putting out today ( in my opinion). My first change would be the scope.
4. Severely fouled bore, pitting and general roughness from a poorly rifled bore ( uncommon with most quality manufacturers but it can still happen). Run a patch soaking wet with a good, strong bore solvent, such as Butch's Bore Shine, Sweet's, etc. and let it set overnight.
5. Poor bedding. High spots in the barrel channel of the stock could be pressing on the barrel, changing slightly from shot to shot from heat, humidity and barrel vibrations.
6. Ammunition. Maybe this particular rifle just doesn't shoot well with the ammunition you are using.
7. Was it accurate when your dad used it? If that is the case then obviously something has happened to it between there and here to affect it's accuracy. Damage, fouled bore, a change in ammunition would be the culprits.

 

[deadkenny]

As has been mentioned, start with the 'easy' (and cheap!) stuff first, before you get into gunsmithing. One question, how long did you wait between shots? With a 'lighter weight' hunting rifle weight barrel, it can heat up after a couple shots and change the PoI. Some rifles seem to just not shoot well with some loads, try another load, preferrably one with a good rep for accuracy (or a good handload if you're into that or have access to it). If the barrel has a fast twist, you might want to try heavier bullets. If it's possible, try borrowing a good quality scope, possibly changing the bases if deemed necessary. If everything is screwed down tight, you're using a good quality properly mounted scope, shooting an already 'fouled' barrel (i.e. don't start of clean, the intial 'fouling' can also change PoI), letting the barrel cool between shots and shooting an 'accurate' load and you're still getting poor results with 3 shot groups, then you might have to get into some of the more labour intensive / expensive gunsmithing solutions.

 

[dakotasin]

41- rugers are very sensitive to the bedding pressure, and cranking it down tight or backing it way off isn't likely to help you much. start w/ that front screw a little more than snug. shoot a group, then turn it 1/4 turn tighter, shoot a group. repeat this process until the groups show something significant.

 

[Jim Watson]

A friend of mine had the same experience with the same make and calibre. He did the easy stuff, he did the hard stuff, he sent it back to Ruger... twice. The first trip they rebedded and recrowned the original barrel which made no difference. The next trip they gave up and replaced the barrel. They sent the rifle back with a 1.5" test target which he thought was not great but ok for hunting... until he saw that it was shot at 50 yards instead of 100.

So he sought out a real gunsmith. The rifle now has a name brand barrel in .280 Rem and shoots like a champ.

 

[41magsnub]

thanks guys!

Great ideas here.

The gun has never had the level of cleaning you guys describe. It has always been to just swab it with bore cleaner, run a brush through a few times, patch it until dry, run a patch saturated with gun ooil through it, then patch until almost dry again. I'll get some foaming stuff and give it a try.

Sadly it has no iron sights so that option is out. It has the mount holes so if I had to I could probably come up with something, but would rather stick with a scope for the testing.

I was giving the gun about 1 minute between shots with the bolt open.

I've got some 160 grain new Remington shells I found on sale that I'll try to see if that changes anything. One flaw of a 7mm mauser is that unless you are a reloader (I'm not) you are kind of limited to what the sporting goods stores carry which varies in bullet type, brand, and grain. I think I'll start getting ammo online to get more consistency.

I'll do an inspection of the crown tonight and see if it looks rough.

The scope is scuffed, but has no damage. It is possible it is beat up though. It frequently rode in the truck barrel down on rough roads stuffed in next to the console. The rings as far as I can tell are fine, scuffed but do not appear damaged. It has standard Weaver rings on it.

 

[41magsnub]

A serious cleaning of the bore is definately part of the issue. I'm on round 5 of a foam cleaning (the gun slick stuff) and the patches still come out both blue and black. Before I started this latest round I ran some traditional bore cleaner and a brush through it a few times to hopefully knock the gunk a little more loose.

 

[Kestrel]

I've read that the 7x57 Rugers have a long leade and require a long bullet to engage the rifling. The 160gr bullets may be a good start. 170gr may be even better.

Oh - the cleaning is a good idea, too.

 

[41magsnub]

Thanks Everyone. I'm back in battery. Scrubbed the bejesus out of the barrel with the foaming stuff, switched up to Federal 175 grain rounds which I know I can find again, and touched up the crown. Took it to the range today and was putting rounds inside a dime at 50 yards, 1" groups at 100 yards and 2" groups at 200 yards. I was a little wild at 300 yards, but any of the shots aimed at the torso of a deer would have been good enough that far. Put 3 boxes of ammo through it to get my confidence in the rifle back.

The gun had historically been shot with Remington factory loaded 160 grains to good effect. I wanted to keep using 160 grain, but I come to find out unless I hand load I will never again find them. Out of production. The only "normal" rounds are 140 grain and 175 grain. I may have the last boxes factory loaded 7x57 160 grain in existance. Excagerating I know, but probably not by much.

I tried the 140 grain rounds again as a fluke since I have them and was back to shooting like a storm trooper. 140 grain = bad in that rifle