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Discussion Starter #1
I'm new here, and maybe this has been answered. If so, sorry--please point me to the post. I searched and didn't find it. Also, I am NOT a gunsmith, but I'm looking for expert answers.

My M-77 with Hornady Precision Hunter, 162 grain, on a sled, produced a 3 inch group at 100 yds, six inches (if you call that a group) at 200, and was crazy at 250. Last year I had the barrel floated and put in a Timney trigger set at 3lbs. Has a new Leupold 3-9x40, bought last year, professionally mounted. I'm the first owner, babied it all these years. Didn't use it for 20 years while deployed in various places, so it's fired 300 rounds or less. Now back to hunting. Somehow I never noticed its low accuracy before.

Why the HECK is it a 3 inch group at 100yds? I suspect it is a poor barrel design or poorly manufactured. Does anyone know? Has metallurgy and manufacturing advanced in the last 35 years?

I did see an "M-77 accuracy tip" post that describes how to file the mag box so it's a little loose. I'm going to do that. But I'm wondering if current manufacturing quality is much better now and I should just sell this and buy a new one.

Is Gunsmithing the right area to post this?

Thanks for any advice.
 

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I'd try shimming the barrel after you try the mag box mod(if your going to) not all barrels like to be "floated".
 

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Discussion Starter #4
I'd try shimming the barrel after you try the mag box mod(if your going to) not all barrels like to be "floated".
Thanks! I did the box mod. We’ll see.
How does the rifle shoot with lighter bullets? Is that the only ammo you have tried?
I usually shoot Hornady SST 139 gr, but I’m hunting mule deer in Oct and want a heavier bullet. At 139gr I think it’s better.
 

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First your rifle has a Wilson barrel.........they were hit and miss in the accuracy department.

Are you torqued to 90 IP? This does make a difference. Have you tried to torque tune your rifle? This generally helps. It’s unusual to see a 7Mag NOT shoot heavier bullets due to the rate of twist. I’m fortunate, mine will shoot light or heavy but I had to do some load development.

My buddy uses the same round in his and it’s lights out out to 600yds. I’ve shot them in mine with similar results.

ETA; Hornady didn’t randomly pick the 162gr bullet for their Precision Hunter line, it’s an ideal weight for the caliber.
 

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Discussion Starter #6
I have a lot to learn! No, I have not torqued it, but I will. Another guy in another forum said to go 95 on plate, 50 on rear and 1/4 turn past snug in the middle. Does that sound right?
 

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I have a lot to learn! No, I have not torqued it, but I will. Another guy in another forum said to go 95 on plate, 50 on rear and 1/4 turn past snug in the middle. Does that sound right?
I stand corrected, it is 95 IP...........90 would do the trick though too. As far as the middle and rears screws, throw both those numbers out the window and here's why. When I asked if you had "torque tuned" I was talking about something specific, totally unrelated to torque specs.

Torque tuning is a process that one does as they are shooting their rifle. Lets address the center/front trigger guard screw, that screw need only be tightened enough to hold it in place......nothing more. Now on to the torque tuning part. When you are at the range back the rears screw all the way out, and screw it back in until you feel it bite. Now stop and take a couple of shots, (2 or 3 your choice) and see how they group. The group any better? No? Screw it in a little more and repeat. Repeat this process until the groups tighten up........I have 4 M77's and have done this to each one and they are all sub MOA shooters if I do my part..........My 7 Mag will print .75 MOA.
Yes it's time consuming but it will pay off in the long run.

One more suggestion I have and would do before I went back out would be a good cleaning with some Bore Tech C4 for the carbon and JB Bore Paste for the copper. Barring a bad float job I can't imagine you barrel being shot out at 300 rounds. A buddy had a rifle that started looking like a shotgun test pattern and was about to sell it and told him to give to me and let me see what I could do with it..........turns out it was severely cooper fouled. A heavy dose of C4, Butche's Bore Shine and some JB and it was back on target.

If I didn't make the tuning process clear let me know.
 

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Discussion Starter #8
I stand corrected, it is 95 IP...........90 would do the trick though too. As far as the middle and rears screws, throw both those numbers out the window and here's why. When I asked if you had "torque tuned" I was talking about something specific, totally unrelated to torque specs.

Torque tuning is a process that one does as they are shooting their rifle. Lets address the center/front trigger guard screw, that screw need only be tightened enough to hold it in place......nothing more. Now on to the torque tuning part. When you are at the range back the rears screw all the way out, and screw it back in until you feel it bite. Now stop and take a couple of shots, (2 or 3 your choice) and see how they group. The group any better? No? Screw it in a little more and repeat. Repeat this process until the groups tighten up........I have 4 M77's and have done this to each one and they are all sub MOA shooters if I do my part..........My 7 Mag will print .75 MOA.
Yes it's time consuming but it will pay off in the long run.

One more suggestion I have and would do before I went back out would be a good cleaning with some Bore Tech C4 for the carbon and JB Bore Paste for the copper. Barring a bad float job I can't imagine you barrel being shot out at 300 rounds. A buddy had a rifle that started looking like a shotgun test pattern and was about to sell it and told him to give to me and let me see what I could do with it..........turns out it was severely cooper fouled. A heavy dose of C4, Butche's Bore Shine and some JB and it was back on target.

If I didn't make the tuning process clear let me know.
Mark204, You explained it clearly! Thank you. I'll do that and report back after the range this Sunday. I just ordered the two cleaning products but they won't be here until Monday. I'll go out again after I use them.

I like Ruger as a company, and own a Ruger Redhawk 44 mag for a sidearm while hunting, but this problem with my M-77 is disappointing. This is my first and only bolt-action hunting rifle--so maybe this is not unusual for a hunting rifle, I don't know. In northern Alabama I hunt with a slug gun, muzzleloader, and crossbow--deer are always 15 to 60 yards away. If I can't get this bolt-action down to one MOA, I will have to buy a different one. I know there are guns that are consistently accurate. I'm going to be hunting out west at least annually from now on.
 

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Discussion Starter #9 (Edited)
I stand corrected, it is 95 IP...........90 would do the trick though too. As far as the middle and rears screws, throw both those numbers out the window and here's why. When I asked if you had "torque tuned" I was talking about something specific, totally unrelated to torque specs.

Torque tuning is a process that one does as they are shooting their rifle. Lets address the center/front trigger guard screw, that screw need only be tightened enough to hold it in place......nothing more. Now on to the torque tuning part. When you are at the range back the rears screw all the way out, and screw it back in until you feel it bite. Now stop and take a couple of shots, (2 or 3 your choice) and see how they group. The group any better? No? Screw it in a little more and repeat. Repeat this process until the groups tighten up........I have 4 M77's and have done this to each one and they are all sub MOA shooters if I do my part..........My 7 Mag will print .75 MOA.
Yes it's time consuming but it will pay off in the long run.

One more suggestion I have and would do before I went back out would be a good cleaning with some Bore Tech C4 for the carbon and JB Bore Paste for the copper. Barring a bad float job I can't imagine you barrel being shot out at 300 rounds. A buddy had a rifle that started looking like a shotgun test pattern and was about to sell it and told him to give to me and let me see what I could do with it..........turns out it was severely cooper fouled. A heavy dose of C4, Butche's Bore Shine and some JB and it was back on target.

If I didn't make the tuning process clear let me know.
One more question before I go to the range: how long do you recommend letting the barrel cool between shots? Also: I just torqued the mag plate bolt, and now my barrel is no longer floated. I have no choice but to shoot the gun as is this weekend. I guess if the shots are wild I can back off the front bolt a little until it floats again.
 

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One more question before I go to the range: how long do you recommend letting the barrel cool between shots?
Vic, I’m guessing I will probably go 5 minutes in between shots with my 7 Mag because it’s a sporter, (buggy-whip) barrel. If you can, stand the rifle up with the bolt open, that will help somewhat to dissipate the heat.
 

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Discussion Starter #11
Vic, I’m guessing I will probably go 5 minutes in between shots with my 7 Mag because it’s a sporter, (buggy-whip) barrel. If you can, stand the rifle up with the bolt open, that will help somewhat to dissipate the heat.
Mine also has a thin skin. I might go 15 min.
 

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Discussion Starter #13 (Edited)
I stand corrected, it is 95 IP...........90 would do the trick though too. As far as the middle and rears screws, throw both those numbers out the window and here's why. When I asked if you had "torque tuned" I was talking about something specific, totally unrelated to torque specs.

Torque tuning is a process that one does as they are shooting their rifle. Lets address the center/front trigger guard screw, that screw need only be tightened enough to hold it in place......nothing more. Now on to the torque tuning part. When you are at the range back the rears screw all the way out, and screw it back in until you feel it bite. Now stop and take a couple of shots, (2 or 3 your choice) and see how they group. The group any better? No? Screw it in a little more and repeat. Repeat this process until the groups tighten up........I have 4 M77's and have done this to each one and they are all sub MOA shooters if I do my part..........My 7 Mag will print .75 MOA.
Yes it's time consuming but it will pay off in the long run.

One more suggestion I have and would do before I went back out would be a good cleaning with some Bore Tech C4 for the carbon and JB Bore Paste for the copper. Barring a bad float job I can't imagine you barrel being shot out at 300 rounds. A buddy had a rifle that started looking like a shotgun test pattern and was about to sell it and told him to give to me and let me see what I could do with it..........turns out it was severely cooper fouled. A heavy dose of C4, Butche's Bore Shine and some JB and it was back on target.

If I didn't make the tuning process clear let me know.
Mark204, and anyone else who's given me advice, here are the results from today at the range. Bottom Line: GREAT results.
But first here is what I did to the rifle yesterday: (1) I floated the barrel myself so that it would float at the correct torgue, (2) at correct torque the safety on my Timney trigger would not move, so I removed wood until the safety functioned again, (3) several days ago I filed the front and back top of the mag box until it moved inside the well, (4) torqued the front bolt to close to 90 IP, torqued the rear bolt to 50 IP, and tightened the center bolt just enough to not fall out, (5) cleaned the barrel with two products that remove powder and remove copper fouling. Barrel and action were CLEAN. Mark204 said to torque tune the rifle, but I only had one hour at the range (for anyone else reading this, see his instructions above for torque tuning). That will have to wait until I have more time. Regardless the results are great. See photos. All shots are with Hornady Precision Hunter, 7mm Rem Mag, 162 grains, ELD-X. The rifle is a Ruger tang safety M-77 made in 1984. I am the original owner. It has fired about 300 rounds.
Between shots I waited 5 minutes to let the barrel cool. I fired at 100 yds and had a 1.7 in group centered and 1.75 high. That made sense since at my last shoot I tried to zero at 250. So I adjust up 1/4 MOA to hit at 2.5 high--what I need for the bullet to hit center at 250 yds. Did not have time to confirm at 100, so went straight to 250. Achieved a TWO INCH group at 250 (!!) centered at 0.6 in low/ 1.25 right. Adjusted 1/8 MOA up, 1/4 MOA left. Time was short, so I quickly tried to confirm the zero with two more shots without waiting between shots. WOW. See third photo. They went wild. This and the next three shots confirm that it is ESSENTIAL to let the barrel of this M-77 cool down when making multiple shots.
Then I fired three more pretty quickly while using a friend's chronograph to check muzzle velocity. Those went crazy too. See third photo with the holes labeled "Hot Barrel". The "group" was 8.5 x 8.5 inches, centered about 4.5 right and 1.5 high. That hot barrel metric is not relevant to hunting because those first shots will always be from a cold barrel. Any time I've had to take a second shot was up close just to put a deer out of their misery if the first bullet didn't kill them (that's happened to me twice). Chronograph measured three shots at the muzzle at an average of 2864 FPS, which is interesting since Hornady rates that round at 2975 FPS at the muzzle. If my ballistics calculator is correct, the lower velocity, zeroed at 250 yards, raises the path 0.3 inches at its peak at 150 yds, and lowers the strike the same difference at 300 yds. Not enough distance to worry about went hunting mule deer or antelope at those ranges.
I also re-learned and re-remembered how critical it is, at 250 yds, to ensure the rifle is vertical and to very very gently sqeeeeze the trigger. A couple of times I was less careful, and that sent the bullet off to right about 8 inches. I disregarded those pulled shots when I measured my groups. That is another reason I need to confirm the 250 zero with a cooled barrel. If I can find the time I will also torque tune the rifle.
Mark240 and others, thanks for great advice. The good news is I don't have to buy a new rifle before my Wyoming trip in October. The bad news is I don't have to buy a new rifle. ;-)
 

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Mark204, and anyone else who's given me advice, here are the results from today at the range. Bottom Line: GREAT results.

I fired at 100 yds and had a 1.7 in group centered and 1.75 high. That made sense since at my last shoot I tried to zero at 250.
First off I'm glad you got the bugs worked out......The thought of replacing a rifle never sits well with me. I also ran your numbers through my Ballistics Calculator so you can see how it compare to yours. Here are the numbers out to 400 yards..........you want your zero to be set at 250yds, correct?

These numbers are based on a 162gr ELD-X, (BC of .670) and a MV of 2864 with a scope height of 1.5". Naturally a diffent scope height will change the numbers but nothing dramatic.

100yds.......+2.7"

150yds.......+3"

200yds.......+2.2"

250yds.......0

300yds......-3.5"

350yds.....-8.5"

400yds.....-15"

As far as MV listed on Hornady's box, (and anyone's for that matter) I've found those numbers to be inflated by as much as 100fps. My buddy shoots a lot of Hornady factor stuff, He actually uses the 162gr ELD-X and his numbers aren't close either using my Magneto Speed. He's run his out to 600yds and its dead nuts accurate at that distance.

Again, I'm glad you got your issue resolved.


ETA; I calculated this with the default settings........
 

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First off I'm glad you got the bugs worked out......The thought of replacing a rifle never sits well with me. I also ran your numbers through my Ballistics Calculator so you can see how it compare to yours. Here are the numbers out to 400 yards..........you want your zero to be set at 250yds, correct?

These numbers are based on a 162gr ELD-X, (BC of .670) and a MV of 2864 with a scope height of 1.5". Naturally a diffent scope height will change the numbers but nothing dramatic.

100yds.......+2.7"

150yds.......+3"

200yds.......+2.2"

250yds.......0

300yds......-3.5"

350yds.....-8.5"

400yds.....-15"

As far as MV listed on Hornady's box, (and anyone's for that matter) I've found those numbers to be inflated by as much as 100fps. My buddy shoots a lot of Hornady factor stuff, He actually uses the 162gr ELD-X and his numbers aren't close either using my Magneto Speed. He's run his out to 600yds and its dead nuts accurate at that distance.

Again, I'm glad you got your issue resolved.


ETA; I calculated this with the default settings........
My calcs are -14.8 at 400, otherwise the same. Scope height is 1.5.
I am a little confused about the G1 and G7 BC for the bullet. Need to research what that means. I used G1 for the ballistics, and guessing you did also.
Next step is to shoot it from a bipod while sitting, and from prone supported off my back pack. It’s ok if the group is wider as long as the group is in the right place.
 

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Vic, here's a little info on the difference between a G1 and G7 drag profile. This was more than likely compiled by Bryan Litz, he's the chief ballistician at Berger bullets. He was the driving force behind the G7 model. Bryan has at least four books to his credit that I know of, he's a member another forum I'm on, (which is kind of nice), and he's also a member of the 2 mile club. Did I mention he was a rocket scientist for US military? He's the reason that Nosler and other companies lowered their G1 BC's..........He ran the tests and called BS. I don't think there is anyone more knowledgeable when it comes to ballistics than Bryan.

There are more links within the one I posted at the bottom, enjoy.


 

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First off I'm glad you got the bugs worked out......The thought of replacing a rifle never sits well with me. I also ran your numbers through my Ballistics Calculator so you can see how it compare to yours. Here are the numbers out to 400 yards..........you want your zero to be set at 250yds, correct?

These numbers are based on a 162gr ELD-X, (BC of .670) and a MV of 2864 with a scope height of 1.5". Naturally a diffent scope height will change the numbers but nothing dramatic.

100yds.......+2.7"

150yds.......+3"

200yds.......+2.2"

250yds.......0

300yds......-3.5"

350yds.....-8.5"

400yds.....-15"

As far as MV listed on Hornady's box, (and anyone's for that matter) I've found those numbers to be inflated by as much as 100fps. My buddy shoots a lot of Hornady factor stuff, He actually uses the 162gr ELD-X and his numbers aren't close either using my Magneto Speed. He's run his out to 600yds and its dead nuts accurate at that distance.

Again, I'm glad you got your issue resolved.


ETA; I calculated this with the default settings........

It looks like you are heading in the right direction! Congratulations on your rifle's new-found accuracy. I might suggest one other thing...if you have the inclination or patience. All of my rifles were before the ELDX bullets, so I didn't get to try them, but none of my Rugers liked SST bullets, although those red noses did look sharp! One or two other brands of bullet may help in your search. Sierra has always had a reputation for good accurate projectiles. and Speer has always done well for me. :)
 

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Discussion Starter #18
It looks like you are heading in the right direction! Congratulations on your rifle's new-found accuracy. I might suggest one other thing...if you have the inclination or patience. All of my rifles were before the ELDX bullets, so I didn't get to try them, but none of my Rugers liked SST bullets, although those red noses did look sharp! One or two other brands of bullet may help in your search. Sierra has always had a reputation for good accurate projectiles. and Speer has always done well for me. :)
Flyboy, I definitely have the patience. And the perseverance. I want to do that. I hate waste. How do I try different bullets without wasting ammo that doesn’t work? Everyone says to try different bullets but a 20 round box is $17 to $45, depending. How have you managed that? Serious question—not criticism.
 

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How do I try different bullets without wasting ammo that doesn’t work?
You don’t, you stick with the ELD-X’s. You’re not going to find a better BC, maybe in a Berger or a Nosler.......but you won’t come close with a Sierra in the same weight class, that’s a fact.

JMO, but I’d set the zero shooting off a bipod and rear bag at 100yds but set your scope to print 2.7” high. You’ll have your 250yd zero and the bipod and bag will help to minimize human error. That’s my routine.
 
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