M77 .300 WinMag Question

[Hoji]

I have a M77 .300 WinMag with the tang safety mfr date around 1990. It absolutely does not like 180 grain ammunition. I do reload( the rounds fired were factory Winchester Supremes)

Any recommendations on what this gun does like? Reloaders chime in, as well as factory load shooters.

Thanks.

 

[Sagebrush Burns]

What you're saying is that it doesn't like that one load. Try some others. And do some loading.

 

[WJU]

LOTS of 180's to try. Mine likes standard 180 core lokts so much I never reload for it.

So many bullets. So many powders...it would take years to try them all work up loads. But that is the fun of it.

Good luck

 

[Hoji]

Should have mentioned that I also shot 180 CoreLokt and 180 Win Powerpoints as well. None under 3".

 

[El Numero Uno]

Check your trigger guard screws. the angled one should be tightened first; "farmer tight"; rear 2nd- tight; middle last -snug. Only advice I have that is mechanical; shoot different loads.

 

[Hoji]

Thank you uno. I will check that.

I will also be trying lighter rounds.

Any reloaders have a favorite recipe for this gun?

 

[keyston44]

The only factory load mine liked was Federal Premium Safari with Nosler Partitions. I have come up with a load that duplicated that load that I shoot in it. 71.0 gr of IMR-4350 with CCI LRM primers in the same nickle cases and the Nosler 180gr Partition. I seat the bullet to just fit in the magazine. That leaves alot of freebore but I still get 5/8" 3 shot groups. I've used that load for over 25 years in that gun and it also works in my wifes MKII.

Key

 

[Hoji]

Thank you. I will give that a go.

 

[shaffe48]

I posted on here before about my Mkii which will now shoot well under an inch with many loads after I tightened the trigger screws. One's supposed to be up to like 90 inch pounds.

Specifically answering the question: .65" with 180 gr SST, Federal Magnum Match, RP brass, 77 gr of RL22. This is max for a 180 gr bullet for the alliant website and it's over max for manuals. However, Lyman does recommend 77 gr, but only with standard Winchester primers. In other words, if you load more than 75 gr of RL22 behind a 180 gr bullet, you want to go slow from what I've read where this is usually max.

Also worked up a load with 180 gr ballistic tips. Got 1.1 inches from 76.5 gr of RL22. Pretty sure I could have gotten better accuracy if I had been shooting fewer groups but haven't tried it.

 

[Hoji]

The scope I had on it( brand new Vortex Viper PST) is developing what appear to be bubbles in the lens. The scope is going back to Vortex for warranty work, I suspect that that may be the grouping problem I was having as most of y'all seem to do very well with 180 grain bullets.

PITA that an almost $1,000 scope has to have warranty repairs done less than a month after buying it, but the person I spoke to seemed pretty sure they could get it back to me in 8-10 days. They also were apologetic about the problems I was having with it.
Will give an update on it in a little over a month. Thanks all.

 

[gramps]

I have a Remington 788 in.308, that hates Winchester 180 gr. Shoots them 6 inch to the left and down 6 inches. So I just stay with the 165 gr BTHP or BTSP, which it adores. Good luck. Guns can be finicky eaters.
gramps

 

[Lloyd Smale]

have you tried any other bullet weights. could be it just isnt going to be a shooter. Ive had two ruger 300wms. One was a great shooting gun that would shoot about anything well and the other was a complete dud.

 

[martyj]

Shoot at 200 yard and give the bullet time to stabilize.

 

[Randomguy]

I have a Remington 788 in.308, that hates Winchester 180 gr. Shoots them 6 inch to the left and down 6 inches. So I just stay with the 165 gr BTHP or BTSP, which it adores. Good luck. Guns can be finicky eaters.
gramps

You know, you CAN adjust the sights to get the thing to hit point of aim :lol:

How does it group?

 

[gramps]

It groups well, but didn't want to change the sights that much. I just kept using 150 gr and 165 gr that shot to point of poa.
gramps

 

[Divernhunter]

My M77 300Win mag shoots well with IMR4350 and RL19 or 22 using 150gr Nosler Partition or 165gr Swift A-Frame bullets at max loads. Then again I use a Leupold 3X9X40 scope which never gives me trouble on most all my hunting rifles. I have one 3.5X10X40 (264Win Mag M77)and one 6.5X20X40(varmit rifle). They just always work.

 

[Kudu m77]

If it was me I would bed the action and free float the barrel. 3" at 100 could very well be a bedding problem.

I apologize if it was mentioned in the thread as I might have missed it.

Pieter

 

[Nomosendero]

The scope I had on it( brand new Vortex Viper PST) is developing what appear to be bubbles in the lens. The scope is going back to Vortex for warranty work, I suspect that that may be the grouping problem I was having as most of y'all seem to do very well with 180 grain bullets.

PITA that an almost $1,000 scope has to have warranty repairs done less than a month after buying it, but the person I spoke to seemed pretty sure they could get it back to me in 8-10 days. They also were apologetic about the problems I was having with it.
Will give an update on it in a little over a month. Thanks all.

That scope offers alot of bang for the buck. A friend has the 6x24x50 that I shoot with, very repeatable adj & incredibly bright. But, we all draw a dud sometimes. I was curious if you have the scope back and shooting.

A couple of great 180's to try is the 180 Sierra Pro Hunter flatbase & 180 Nos. BT. These are very accurate bullets plus you can see if you rifle has flatbase or boattail leanings, it happens sometimes.

Also, I see no indication that you have tried other weight bullets. Even though an 06 or 300WM will usually shoot a 180 well, some rifles just prefer a certain bullet weight & at times an identical rifle will prefer another weight, I have seen that one played out several times. I am curious how a 165-168 would shoot.