Ruger 77/44 bore diameter

[Steve E]

My 77/44 hasn't been wanting to shoot very good with cast boolits so I slugged the bore and came up with the following measurements, .422 & .433. It might be hard to find a boolit mold that will cast .434. Has anyone here with one slugged their barrel yet?



Steve E............

[Nobade]

Yep, I had one that measured the same. I never have figured out why the manufacturers can't seem to make 44 mag barrels the right size, when they can do all the other calibers just fine. Anyhow, Ranch Dog has moulds that will fit, and work well. You can also paper patch regular 44 bullets to the right size. You will also probably find out that a correctly sized bullet doesn't even need the case resized to fit right. Double bonus there!

BTW, I have had Handi rifles, Contenders, and a Browning B92 that all were about .433" Ruger isn't the only guilty one out there! I eventually changed the barrel on my 77/44 to a Shilen fast twist one to shoot really heavy boolits subsonic. It worked great until somebody offered me too much money for it and it went away.

[williamwaco]

Steve,

I have a sneaking suspicion that you got those measurements with a caliper. If you did, try to find someone with a micrometer to verify them for you.

My Ruger slugs .4168 / .4288
I use .430 bullets in it with good accuracy and no leading.








.

[mdi]

When I first got my Puma I slugged the bbl. and found it oversize, .432". Did some research and found the SAAMI specs. are different in .44 Magnum pistol vs rifle. Barrel dimensions for pistol according to SAAMI; .417" and .429". Rifle diameters are .424" and .431". So, I figger anything from .429" to .431" is in spec for groove diameters and add factory tolerances (slop) will mebbe go up to .432" to .433" for .44 Magnum. Even knowing factory "supposed to be" sizes, it's still good to slug yer bore.

I went with a Ranchdog .44 Magnum 265 gr. RFN mold ( drops bullets at about .433") and one of his Lee sizing dies at .432" and it works well in the Puma (also shoots good in my other .44s)...

[dbldblu]

If you do a chamber cast, you may find a sloppy chamber, I did. Mine will only shoot well with 300 grain, I guess that bridges the gap better.

[Steve E]

I measured the slug with my mic and it was .4314. It shoots fairly well with the 250 gr. XTP HP's. The only cast bullets I had on hand was some I cast about 10 years ago and are 240 gr. SWC's that were sized to .429. Not sure why I sized them to .429 but they don't shoot very well, I remember they didn't shoot very well in my Ruger SBH either.

Steve E........

[Blammer]

I slugged mine and a came out to .430 as I recall.

[softpoint]

As an added bonus for the Ranchdog boolit, my 77/44 will feed them when seated to the crimp groove. Other boolits, especially SWC, have to be seated ahead of the front band to work in the magazine, and then they still don't feed well.:coffee:

[Steve E]

I believe the cast SWC I tried was from a Lee 240 gr GC mold. I crimped it in the crimp groove and it fed fine. Just too bad it didn't shoot worth a darn.
I originally bought this rifle to rebarrel it to 357 x 44 B&D but am wondering if it being in the first year production for the 77/44's would make it worth keeping original.


Steve E..............

[BarryinIN]

Mine is .430. I've not done a chamber cast.
Mine likes the Ranch Dog 265 about as well as anything.
It's from the first time around, before they stopped making them for a while, if that matters.

Softpoint- I've only heard good things about how well they feed. Mine has fed everything that fit in the magazine, from the old Lyman 429105 whose nose is hardly a bump, to the Lee wadcutter, to more conventional shapes.
I don't know if it makes any difference, but I have noticed my two magazines differ a little, at least on the outside and the spring pressure feels different. I got my rifle used and those mags came with it, so I have no idea which was made first or if there is enough difference to do anything.

[cabezaverde]

If you are looking for a PB mold, I have an LBT for sale in the classified area.

[mdi]

I measured the slug with my mic and it was .4314. It shoots fairly well with the 250 gr. XTP HP's. The only cast bullets I had on hand was some I cast about 10 years ago and are 240 gr. SWC's that were sized to .429. Not sure why I sized them to .429 but they don't shoot very well, I remember they didn't shoot very well in my Ruger SBH either.

Steve E........

What happened to .433"? Misread the first slug? Anyway that is still "in spec." ,.431", and it shouldn't be hard to find .432" bullets. If you want to try .432" bullets before you buy a mold, buy some from Beartooth. They have bullets from .429" up to ,432"...
http://www.beartoothbullets.com/bulletselect/index.htm

[W.R.Buchanan]

Here's the reason they make bores on these rifles on the large size. Pressure! It's a lawyer thing.

.44 mag is a 35,000 psi cartridge, and small changes can result in big changes in pressure. Just using the wrong primer can spike pressure 10K psi ! Marlins are good to 43K ish, your bolt action should be good much higher but beyond that is the danger zone.

They make the bores loose so that the pressure doesn't get out of hand with factory loads and Jacketed bullets, and hot handloads.

I was told by Marlin that Industry Standard bore size for .44 mag. is .431+/-.002

Marlins also have 1:38 twist barrels which don't help accuracy either. Your's should be 1:20 twist. Somebody came up with the 1:38 twist number along time ago and nobody ever did anything to change it. The short fat bullets would tend to be classified as an "Express" type of loading and most of those type rifles had slow twists. Some as slow as 1:60 IE .45-90 type loads.

I personally don't see why the industry can't standardize for this cartridge, and with modern machinery there is no reason for consistancy problems. Problem is this industry does tend to be "tradidtional" in nature and very conservative in it's development strategys. Things don't change rapidly, Except when we have a real War!

But then again this same type of thing exists with the .44-40 and .45LC too. Every company has it's own ideas about what they want to do, and whats right.

I guess you have to learn how to make what you've got work. The .44 magnum is NOT a super duper accuracy cartridge in any event, and I'd say if you can get below 2" at 50 yds then your doing pretty good. Better than that will be a gift. I've seen several guns do it but they were NOT generic guns, and were definately the exception.

my .02

Randy

[Steve E]

mdi

I don't think I was holding my mouth right when I used my caliper. LOL.
Thanks Guys for all the info.

Steve E........