Ruger M77 Build Question 7mm LRM

[Wapiti1]

Guys,

I am looking at rebuilding my M77 MK2 and chambering it in 7mm LRM (7mm-375). How well will this fit given the relatively short 3.4" (compared to Remington) mag well of a Ruger?

I know that the parent 375 Ruger fits fine, but the bullets for that are generally loaded to the cannelure and crimped, so they always conform to the SAAMI max COAL.

I am worried that the long 7mm bullets may make this too much of a compromise.

The donor rifle is a .300 win mag that I just no longer use. I will do the machining work on the action and barrel myself. I am just not sure how the combination will work with this cartridge since the only 7mm LRM's that I have seen were on Remington or Remington clone actions with 3.6"+ long magazines.

What do you think? Go with a shorter cartridge, or do it and see?

Jeremy

 

[AaronSkipDavidson]

Guys,

I am looking at rebuilding my M77 MK2 and chambering it in 7mm LRM (7mm-375). How well will this fit given the relatively short 3.4" (compared to Remington) mag well of a Ruger?

I know that the parent 375 Ruger fits fine, but the bullets for that are generally loaded to the cannelure and crimped, so they always conform to the SAAMI max COAL.

I am worried that the long 7mm bullets may make this too much of a compromise.

The donor rifle is a .300 win mag that I just no longer use. I will do the machining work on the action and barrel myself. I am just not sure how the combination will work with this cartridge since the only 7mm LRM's that I have seen were on Remington or Remington clone actions with 3.6"+ long magazines.

What do you think? Go with a shorter cartridge, or do it and see?

Jeremy

The std reamer will have a hybrid at about 3.45" OAL, if you used a VLD, it would be quite a bit shorter. Go for it!

 

[MudRunner2005]

Guys,

I am looking at rebuilding my M77 MK2 and chambering it in 7mm LRM (7mm-375). How well will this fit given the relatively short 3.4" (compared to Remington) mag well of a Ruger?

I know that the parent 375 Ruger fits fine, but the bullets for that are generally loaded to the cannelure and crimped, so they always conform to the SAAMI max COAL.

I am worried that the long 7mm bullets may make this too much of a compromise.

The donor rifle is a .300 win mag that I just no longer use. I will do the machining work on the action and barrel myself. I am just not sure how the combination will work with this cartridge since the only 7mm LRM's that I have seen were on Remington or Remington clone actions with 3.6"+ long magazines.

What do you think? Go with a shorter cartridge, or do it and see?

Jeremy

If you are stuck on OAL with a long high-BC 7mm bullet, look more towards the 7mm Nosler. It's a .26 Nosler necked-up to a 7mm bullet. Should be a rockin round in theory.

Or you could just stick with a regular 7mm RemMag and be perfectly fine with OAL in the Ruger, and still get good velocities of 3,000+ with a 168gr Berger.

 

[Wapiti1]

Thanks for the replies Skip and Mudrunner. I kind of thought my question died a lonely death.

I thought about a 7mm remmy, but would like the extra capacity for 180gr bullets. If possible, I would like to hit 2900-3000fps with a 180 and not have to push the case to its limits.

If an OAL of 3.45-3.5" will work out, then I may as well give it a go. I think that I can stretch the Ruger mag well a little without having to do any extreme machining. I have a Bartlein barrel waiting, now I have to get it built.

I really love the Ruger action, it just never lived up to my hopes with the factory barrel.

 

[MudRunner2005]

Going from standard mag to ultra mag you might have to have the feed rails machined and opened up to accept the larger ultra cartridge width.

If you can extend the magwell, look into the 7mm STW. It will definitely push the 180's 3000-3100, and you can find good brass and won't have to re-form them, then fire-form. Factory ammo is 3.600-3.650", so you wouldn't have to open the mag well up much.

 

[Wapiti1]

I have a Savage in 7mm STW. Great cartridge for sure. This one is more of a project rifle to play with and learn on. I don't work on many Rugers and want to learn the action better.

The 7mm LRM looks like a potentially good fit and gets to the ballistics that I am after. Besides, it is different, and sometimes different is all the reason you need.

The standard Ruger action is difficult to open up to 3.6". They have to be machined all at the back of the mag well, and as I understand it, a bolt stop has to be custom made. That is too much work for this project.

Yes, feed work may be needed. Then again, it may work fine. Ruger stuffed the .375 and .416 in there and in the two that I examined, the rails look the same as on mine. The mag box even looked the same.