30/30 Thoughts - Marlin

M

MW65

Wetside, Oregon
Starting to work on loads for the 336, and wanted to get opinions on what I'm planning.

It's a 1984 mfg 336, and have these 3 moulds I'm planning on...

NOE (RD) 311-171 RF
311291
Rcbs 30-180

I really wanted the RD to fit/chamber in the marlin, but I have to seat wayyyyyy low. I know there's a couple different versions depending on the year of mfg & throat dims, but thinking this is a no-go (oal=2.421").

311291 has a nice 'scuff' fit, and easy to load. As cast is fat, but easily sized to .311

Rcbs 30-180 is slightly skinny .3105ish, but like 311291, has no issues with loading & feeding.

Plan: try rel7, 3031, h335, h4895 with the '291 & rcbs. Size at .311, and try .312 in the '291 to see if it feeds and functions, and how it groups.

Thoughts from the peanut gallery?
Thanks! -Andy
 

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Rick

Rick

Moderator
Staff member
I had pretty good success with the RCBS 180 SP. Mine is a Winchester 94 with a 26 inch barrel. I am the third owner of it, the first two could not get it to shoot anything, here's why . . .

DSCN1844.JPG

That edge is where trimmed case length reached, no throat, it had left the factory that way. A throating reamer solved the problem and it is now a fine shooter. Mostly I used 19 gr IMR 4759 and the RCBS 180 was about 1950 fps.
 
J

Jeff H

NW Ohio
shuz said:
Try some Red Dot around 10g and report back.
Click to expand...
If you don't have/can't find Red Dot, I use 7.5 grains of Unique behind the 4th(?) iteration of the RDO 311-165RF. I have not chronographed it but it should be around 1200 fps.

Oh, not a Marlin, but a 24" MGM Contender Carbine.

If I had one of those short-throated 30/30s, I'd follow Rick's lead and throat it. I don't think there was an actual real reason for the no-throat 30/30s, they just happened.
 
M

Mainiac

Well-Known Member
I have a 1948 336a,,first year of the 336.
It has short throat,and to tight chamber neck,for cast.
Shot cast terrible!!
Finally figured out,to use .007ish neck turned cases,,and the ol girl shoots the ranchdog,,very nice!
 
P

popper

Well-Known Member
Mine shot the original RD, it's a 2010 336 version. Used LeverE and H4895 but 3031 or IMR4895 work also.
 
fiver

fiver

Well-Known Member
that's quite the nose on that [i don't even wanna call it a] ranch dog mold.
 
JWFilips

JWFilips

Well-Known Member
Don't worry the RD 311-171 works great in my JM Marlin from 1970! Set the seating depth to the engagement point.
Seat a dummy round out long (with a semi loose neck) and carefully close the lever then extract the round again carefully and catch it in you hand!...Measure it and That is your COL . Start your loads out lower then max and see the best group.
 
Outpost75

Outpost75

Active Member
The Marlin Microgroove barrels have shallow rifling such that the land-to-land diameter which the bullet fore part needs to fit is larger, generally .302-.303" diameter vs. .3000-.3015 for a conventional 6-groove.

Simplee test is to try the fit of bullet nose into muzzle of your barrel. If the nose enters with little or no resistance up to the front driving band, the nose is unsupported and may "slump" upon initial shot-start and accuracy will be poor.

You want the bullet nose to be a snug fit in the lands when forced into the muzzle with hand pressure only. Upon removal you want the parallel-sided forepart to be visibly engraved by the lands. Such bullets will be accurate even in full-charge loads.

Accurate 31-155D is the plainbased and 31-171D the gaschecked version dimensioned to fit Marlin Microgroove barrels or conventionally rifled barrels having been shot a great deal and having worn origin of rifling.
 
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M

MW65

Wetside, Oregon
Rick said:
...That edge is where trimmed case length reached, no throat, it had left the factory that way. A throating reamer solved the problem and it is now a fine shooter. ...
Click to expand...
Thanks Rick! How difficult is this job? Home gunsmith doable?

Looks like brownells has the reamer I would need...

At crimp groove, oal=2.480...
Oal when deep seated to function =2.421
Delta =0.060 +/- doesn't take much!!
 
Rick

Rick

Moderator
Staff member
MW65 said:
Thanks Rick! How difficult is this job? Home gunsmith doable?

Looks like brownells has the reamer I would need...

At crimp groove, oal=2.480...
Oal when deep seated to function =2.421
Delta =0.060 +/- doesn't take much!!
Click to expand...

Was extremely easy for me, I just handed it to my smith who already had the reamer, didn't even charge me. :)
 
Ian

Ian

Notorious member
This will really screw y'all up.

My 1966 336 Texan that has the auditorium throat and .304" groove puts these together in ragged-hole groups and the nose never touches anything but air until it meets the target.

20201007_224438.jpg

20201018_135922.jpg
 
3

300BLK

Well-Known Member
Marlin has changed 30cal bore and groove dimensions several times over the years. I found this on the 'net.

1955 to 1957 - 16 grooves / .304" bore /.308" groove dia.
1958 to 1968 - 22 grooves /.304" bore /.308" groove dia.
1969 to present -12 grooves/.302" bore /.308" groove dia.
 
Rick

Rick

Moderator
Staff member
Jeff H said:
Did the standard change at some point or did manufacturers suddenly start following it?

I don't remember anyone having issues with no-throat 30/30s until.... twenty years ago?
Click to expand...

The 30-30 Winchester I showed the picture of is a 1968 Commemorative.
 
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