I have a ruger m77 .257 Roberts and i can put a few bullets touching and the next two or three will be off the map I've changed the scope same result I took the human error out by using a lead sled any ideas?

How rapidly are you shooting? Barrel may be heating up causing the disperal in the latter shots. This is pretty typical for light weight barrels.

Don't know if your problem is the same or not but my uncle had one that the bullet would tumble after the barrel got hot. Shooting it you really couldn't hear it. But if u stepped back always and listened with no muffs you could definitely hear what was happening. Doesn't make sense I know but it did happen.

Yea it only does it after about 5-6 rounds through it kinda weird!!

If your first 2 or 3 shots are touching, you're in great shape. Let the barrel cool down after that. The biggest enemy of the gun bore is heat.

A light weight sporter is not designed for rapid fire.

I usually shoot 2-3 then let it cool for a while its hard to sight one in if you can't shoot it more than that in a day but that maybe what I have to do

I had a high dollar custom 257 Roberts once that would only shoot
an 85 gr projectile, one kind of powder and primer and it did that poorly...but it had a Birdseye Maple stock and a custome Mauser Action and Trigger and was really a looker..Never would get another one..DD

An old trick I learned the hard way with Ruger 77's...

Get the biggest longest best fitting screw driver you can find and ...with the gun upside down in a padded vise and NO pressure on the stock anywhere around the receiver...then ATTEMPT to unscrew the front reciver screw. The Front Screw should be super tight out of the factory, and may even make a "crack'ing" sound when it breaks loose from laquer stock finish buildup from not allowing the stock finish to completley dry out before the barrel'd action was installed.

DO NOT bugger the screw head slot !!!!

Then unscrew the rear receiver screw and lift the barreled action out of the stock. IF the stock binds without the receiver screws in place THAT's your answer the stock is binding on the receiver or barrel or both after a few rounds....and you'lll need a rubber hammer to gently tap the stock off the barreled action.

If you see a slicked off shiny place anywhere in the Barrel Channel then THAT's your 1st answer ... the barrel is moving slightly with heat as normal and the barrel is not allowed to "FLOAT" and is spraying bullets from being pushed out of "sync" by the stock or barrel channel. Barrels have a definitive "harmonics" reverberation with the passge of a bullet that MUST be allowed to occur unobstructed...or touching a preplaced barrel bedding block like old SAKO's used & I always removed LOL!

You can also have a binding problem in the stock with the magazine too...so look for shiny wear spots on the walls of the magazine well inside the stock. New Haven M70's can have this problem too....sloppy workmanship!

Both of these problems will be cured with a 'glass bed & barrel floating job by a competent 'smith or hobbyist.

IF NONE of these things are seen, then re install the barreled action, and GENTLY tighten down the REAR screw to not more than Barely Firm, and tighten down the front screw to not more than Touching FINGER tight...and go shoot the gun....3 rounds then tighten the front screw a HALF Turn and shoot 3 rounds until you hit the Sweet Spot of tension on the front screw. Then Gently tighten the rear screw the same way a half turn at a time to Full Firm. You may have to balance the tension but the rear screw being seated just at the Barely Firm setting will not allow the receiver to jump/fall out of the stock as long as the front screw is engaged in the threads at all...the tension of the front screw is an adjustment setting pulling the recoil lug deeper & tighter into the stock recoil plate the heavier the tension is ...and it may not need as much as you might think.
Again the easy answer is to have a 'glass bedding & float job done.

The key thing you said is that you are getting satisfactory accuracy out of a cold barrel for 3-4 rounds...then things begin to move with even minor heat buildup...that tells me you have a stock binding issue of some sort and where to begin the issue resolution at.

77 Rugers are notorius for the 45* angled front screw being OVER tightened out of the factory ...which jam's the receiver recoil lug at a bad angle in the stock and not seats the lug squarely with the barrel binding in the channel as a result. BTDT

OBTW Fiberglass stocks have their own set of similar but different problems...

I had traded for a clean used 1st Gen Wby FiberClass 300WbyMg with the skinny stock & weighed only barely over 7lbs that drove me nutz spraying bullets vertically only. Side to side groups were 1/2" wide & 4-5"s tall.

Pulled the stock off and freaked when I saw the shiny stretch several inch's long under the barrel where the front of the stock was sliding back and forth along the barrel on recoil...and realized the stock was toooo thin around the receiver and was "FLEXING" under recoil. no easy fix except for a new stock with a custom fitted aluminum bedding block like B&C's new Medallist has now ...and the gun "WENT AWAY" down the road. Allus wondered why Weatherby Disc'd those guns...they were a Warranty nighmare...and my Previously Owned rifle had NO Warranty.
Cheers
Ron

You didn't say if it was the ultralight or not--or I missed it. My M77 Ultralight in .257 Roberts does that as it heats up. That barrel is pencil thin, so if yours is the ultralight, I'd say it's normal.

I love that cartridge and that rifle, I've had it 20+ years, it was my first deer rifle!

+1 on what Punkin pointed out on UL's and their Pencil sized barrels...
Cheers
Ron

I have no idea if its ultralight or not its a youth model it was my first deer rifle my dad bout it for me when i was 12 its in meant condition I just wanna get it right it just started this a few years ago!

A 77 UL will have a black plastic tip on the stock and the barrel will be 20"s long from the mid point of the front receiver ring to the crown of the barrel. The front part of the stock will be real slim too.
Might want to take it to a good gunsmith and have him check it out before you go twisting stuff you are not familiar with. It cost me lots of bux to pay somebody to fix my attempts at "fixin stuff" when I started out. Sounds like this gun has more than just a passing value to you if you were not to do the Right Thing.
Cheers
Ron

Ruger 77 - 257 Roberts = one fine combo! I agree that letting the barrel cool between groupings makes sense. In the 'real world', if you don't kill it in 3 shots you're undergunned for whatever you're shooting at.

I just picked one of these up in ultra light. Need to find rings for it first then I can tell if mine acts the same way.

Just a question..If the first few rounds are touching, why screw around with it??
If you know where its going to shoot, how many rounds does it take to kill the biggest buck that ever walked??

My 25-06 does the same. First 4 shots are inside a quarter at 100 yards. Shot number 6 - 8 start moving 1 to 1 1/2 inches away, If shot within a 15 minute period. If I shoot 4 then let it cool down for 30 minutes. Next 4 shots are inside a quarter.

Yea I guess maybe I'm being too picky about it probably I also have a set of rings for sale for the same gun there just not the right color for my gun

+1

I have had several used Model 77's and invariably their barrels
had to be cleaned vigerously before they would shoot. The shock issues mentioned in other posts can also result in
them shooting fine at first, then varying. Clean the barrel
well with Sweet's and use it until you don't get any green
on the swatches. As to the stock, if you even suspect it is not free floating, as has been suggested, then bed the stock. JEM

Like some of the others have said, if it shoots 3 or 4 rounds into a nice small round group before it heats up and starts stringing them, leave it alone. Don't go messing with something that doesn't need fixing. Generally I'm into floating the barrels, but I have two rifles that shoot better non-floated. Both of them have thin barrels (Ruger 77 Compact in 260 and a Ruger Ultralight in 270).

As for the Sweet's, I much prefer Boretech Eliminator. You can clean a barrel with an ammonia based copper remover like Sweet's and then use some Boretech in the barrel and you'll find a lot of copper you just thought you removed. That said, a lot of barrels don't shoot their best when completely cleaned. I've got a couple that shoot better when they are moderately fouled. That's an individual rifle thing, and you'll have to experiment with yours to find if your rifle shoots best squeaky clean or fouled. My Ruger 223 likes to be moderately fouled, and it's slow to foul, so I can run a lot of ammo through it before it needs cleaning. I've found that just Shooter's Choice works best in that rifle. Just take the carbon fouling out and don't mess too much with the copper. My Ruger 220 Swift fouls faster and needs more cleaning.