MKII COMPACT ACCURACY PROBLEM

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sgt 0311

Bearcat
Joined
Jun 24, 2006
Messages
2
Location
usa
I cannot get my MKII compact in 7MM08 to group at 100 yds. Can anyone offer a solution? I was on a USMC rifle team so I do know how to shoot. The rifle has Zeiss scope and I am shooting off a sandbagged bench using 139 gr SSt and 33 gr Varget. This situation is making me crazy
 

Firsttimegrampa

Single-Sixer
Joined
Aug 22, 2004
Messages
284
Location
Havelock,NC USA
Be prepared for some dumb questions- Have you tried diffrent ammo with the same results ? If not try another brand of ammo and see. Will wait for your answer before going further..
 

wwb

Hunter
Joined
Nov 18, 2004
Messages
2,800
Location
wisconsin
First, the bad news.... The M77 MK II rifles were noted for having accuracy problems, and yours may be one of them that just can't be fixed. Sending it back to Ruger may help, but there's no guarantee.

The torque and the torquing order of the mounting screws will make a difference in the group size... this was also true of the original M77. I have an original M77, so I can't help with the MK II, but somebody here may have the numbers.

Sometimes the MK II rifles will improve by floating the barrel.... if that doesn't help, then you can reintroduce a pressure bearing point near the end of the forearm, trying different shim thicknesses to change the amount of pressure.

As Firsttimegrampa said, try some different ammo. Flat base bullets usually will group tighter than boattails, but won't have as good a ballistic coefficient.

Best of luck with your rifle - let us know if it works out.
 

Trey Whitley

Single-Sixer
Joined
Oct 17, 2006
Messages
158
Location
Texas
That stinks. I have a Frontier in 7mm-08, very similar to your compact, and it shoots great with absolutely no mods at all.

Can you be more specific than "cannot get it to group"? Is it all over (and off) the target, or just not as small as you'd like?

To date I haven't had any accuracy problems with the six MkII's I've owned (from 6.5x55 to .375 H&H) but I have improved the accuracy of a couple of them by having my gunsmith bed the action, free float the barrel, and lap the lugs.
 

luvmyruger

Blackhawk
Joined
Sep 12, 2007
Messages
669
Location
Upstate NY
wwb":228h8m11 said:
First, the bad news.... The M77 MK II rifles were noted for having accuracy problems, and yours may be one of them that just can't be fixed. Sending it back to Ruger may help, but there's no guarantee.

The torque and the torquing order of the mounting screws will make a difference in the group size... this was also true of the original M77. I have an original M77, so I can't help with the MK II, but somebody here may have the numbers.

Sometimes the MK II rifles will improve by floating the barrel.... if that doesn't help, then you can reintroduce a pressure bearing point near the end of the forearm, trying different shim thicknesses to change the amount of pressure.

As Firsttimegrampa said, try some different ammo. Flat base bullets usually will group tighter than boattails, but won't have as good a ballistic coefficient.

Best of luck with your rifle - let us know if it works out.

That was in older early 70's rifles.
since then, Rugers rifles are very acceptable hunting rifles. most sub moa. Now, if you are trying to get .16 groups, then you probably have the wrong gun, but not many factory rifles do that anyway
 

Leucoandro

Single-Sixer
Joined
Jun 29, 2006
Messages
448
Location
Dededo, Guam
+1 with what luvmyruger said. The early 70s M77's barrels were contracted out to different companies, so quality was questionable.


WWB is correct about the order and torque applied to the stock/reciever attachment. I had an M77MKII that shot very good groups, but I did not like the trigger. I took it to a gunsmith to fix up the trigger. When I got the rifle back the trigger was awsome, but the rifle was shooting 3" groups at 100 yards with the same ammo that it had shoot .60"groups at 100 yards with before. I finally figured out that he did not tighten the screws securing the reciever to the stock in the correct order. Groups shrunk once again.

As I try to eek out as much accuracy as I can from all my firearms, I now have one of the Wheeler Inch Pound torque drivers available from MidwayUSA.

Also, you should check what your rifling twist is to see if you have picked a good bullet weight. An example is that standard 308 twist is 1 in 12, but my M77MKII VLE has a twist of 1 in 10".

As it seems you reload, also try a different brand of bullet. I am partial to the Nosler Accubond Bullets, they also typically have less expensive target hollowpoints to match there ballistic tip bullets.


Charlie
 

MikeJinVT

Single-Sixer
Joined
Nov 3, 2005
Messages
330
Location
Clarendon, VT
Try the same weight bullet in a flatbase. I had a Ruger No 1 in 270 that would not shoot the 130gr SST's for beans, but the same load with the plain old interlock flatbase was near moa.

Mike
 

sgt 0311

Bearcat
Joined
Jun 24, 2006
Messages
2
Location
usa
Thanks to everyone for the exellent suggestions. Once again this forum has helped me.
Leucandro hit the nail on the head with his experience with trigger job and gunsmith. That was exactly my own scenario.
I just received an email from ruger.
" WE use Federal 140gr when test firing (bullet)??. "Our standards for this is 2" at 50 yds". (not very high standards when they have the best conditions possible) "Check the front mounting screw (under the floor plate hinge) should be torqued to 95 inch pounds. All other screws should be hand tight and then backed off 1/8" of a turn"
Anyone know what 1/8 inch of a turn is? Just being picky.
Off I go to find a torque wrench and buy some bullets.
Thanks again guys.
 

Leucoandro

Single-Sixer
Joined
Jun 29, 2006
Messages
448
Location
Dededo, Guam
sgt 311,

I got this from someone about 2 years ago, I follow it when tightening my M77 MKII's.
_____________________________________________________________

The sequence and torques are:
1. The diagonal screw, torque to 50-90 inch-pounds.
2. The aft trigger guard screw, 30-50 inch pounds.
3. The forward trigger guard screw, also to 30-50 inch pounds.
The torque values will have an effect on barrel harmonics. Ruger uses the upper limits when assembling. But some experimenting may be helpful if you want to tweek the last little bit of accuracy out of the rifle

**Sometimes just adjusting the torque on the diagonal screw will make all the difference as far as group size. I usually do it in 5 in-lb increments. Just remember it's 35 in-lbs minimum and 90 in-lbs maximum on the diagonal screw; 30-50 on the trigger guard screws.
 

Sig685

Single-Sixer
Joined
Oct 21, 2003
Messages
177
Location
Texas
sgt 0311":39wa4ubu said:
I cannot get my MKII compact in 7MM08 to group at 100 yds. Can anyone offer a solution? I was on a USMC rifle team so I do know how to shoot. The rifle has Zeiss scope and I am shooting off a sandbagged bench using 139 gr SSt and 33 gr Varget. This situation is making me crazy

I agree with what has been said above with respect to making sure the rifle is nice and properly tight; those are some solid recommendations. But allow me to go after the problem from 2 more angles.

Ammo.
First off, ignore the calls to drop the SST, it's a fine bullet. But if I were you, I would do is review the load. The Hodgdon website show the range of a load of Varget (a fine powder, BTW, my favorite,) to be from 40.5 to 43.5 grains. So your 33 grain load is woefully inadequate. I would go for a complete load development using proper loads.

Now each bullet has multiple accuracy nodes and you need to find one or more for this bullet. I would start at 40.5 and go up in .5 grain increments to 43.5, shooting a 3 shot group (this is ahunting rifle, not a match rifle) as best you can and see if you can find an accuracy node.

If you cannot find one, do try another bullet, maybe a 130gr Sierra SMK or some other bullet fitting your requirements (hunting or paper punching.)

Also, you have not told us how long you have been a handloader, maybe you just suck at it and need more experience. Certainly the choice of load does not make me comfortable. In that case, I would buy a box f premium ammo in 7mm-08 and see what the results are. Lots of people think they can just roll their own bullets and they are better than factory ammo, it does not work that way.


Scope/mount.
If the rifle is tight (and you have really cleaned it well,) and factory ammo won't shoot, maybe there is something wrong with the scope. Check the mounts, make sure they are nice than tight and maybe even try the scope on another rifle known to be accurate. Or use another scope that is known good and put it on this rifle and check.

If after all this, nothing works, then maybe the barrel is just lousy.
 

Con

Bearcat
Joined
Jun 17, 2008
Messages
72
The action tightening specs are interesting ... my best accuracy comes from:
Front as tight as can be. Rear screw firm, middle just snugged up to remain in there. Going overboard with the middle screw can play merry havoc with accuracy.
Cheers...
Con
 

6mmsl

Single-Sixer
Joined
Jun 8, 2009
Messages
153
Location
Utah
All great advice. Plenty of individuals getting great results on this site with same suggestions.

I would not tear into that new rifle until the easy fixes are addressed ammo, screws,etc.

I would not pay attention to MK11 rifles are noted for accuracy problems, been hearing this comment for years,this comment is bogus.

Good shooting, Steve
 

wwb

Hunter
Joined
Nov 18, 2004
Messages
2,800
Location
wisconsin
steve land":32it6dle said:
.......I would not pay attention to MK11 rifles are noted for accuracy problems, been hearing this comment for years,this comment is bogus.......

You've been hearing it for years because it is NOT bogus. Some of 'em shoot, but far, far too many of 'em don't.

I bought a Mark II in .243 because I liked my original M77 in .30-06. I could not get that thing to shoot a group to save my soul, and my son had an '06 that never shot better than a 4" group. Both were tried with the barrel floated, screws tightened every which way imaginable, business cards under the barrel at different spots, handloads, factory loads,.... nothing worked. Sold both of them to some folks we hoped to never see again. For the record, I replaced the .243 with a Savage 12FV in .223, and it shoots a 5-shot group under half an inch. My son got a Savage 111 in .30-06, and it shoots a 3-shot 3/4 inch group.

The recently introduced Hawkeye is said to have addressed the accuracy problems that plagued the M77 Mark II. Ain't tried one, so I can't pass judgement on it.
 

sarco001

Bearcat
Joined
Oct 13, 2009
Messages
5
Location
West Michigan
Sgt0311,
The torque of the mounting screws is critical, as is the tension on the barrel at the forestock.
On one of my compact M77 MkII's, I relieved the contact area to two points at 4:00 and 8:00, creating a 'V' for the barrel to rest in. This worked for this rifle with a laminated stock.
I mount the scope with the bases slightly loose, in order to help align the rings to the scope body before tightening the bases.
A trigger job will help as well. I have found that the later the model (newer) the rifle is, the more it needs the trigger reworked.
By the way, I tighten my M77 MkII screws to 95 inch pounds on the front angled screw and 55 inch pounds for the trigger guard screws.
Some people have found that increasing the tension on the barrel at the fore-stock has helped.
If you have a Ruger from the eighties, pray. Ruger outsourced the manufacture of their barrels back then and they suffered for it. In the nineties, they began making their own barrels again and did away with the barrel issues that most people refer to when they talk about accuracy issues.
Good luck and let us know how you make out with this rifle.
 

Silent Sam

Blackhawk
Joined
Feb 26, 2006
Messages
728
I for one don't believe that MkII rifles are noted for accuracy problems. Whatever "issues" there were with outsourced barrels is history. I don't see how the introduction of the Hawkeye would have any effect on accuracy as the changes are completely cosmetic. The selling points are matte finishes, wrap around checkering and a different color recoil pad. The only other difference is the rollmark.
 

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