MY buddy has a 1894 CL Marlin chambered in 25-20 made in the early 80's he bought in new condidtion and has been having trouble getting it to shoot. The load he is using is the factory remmington 86 gr jacketed soft point. This gun shoots a shot group at 50 yards with less than a hundred rounds through it.

Can anyone help decifer the problem. So far his theory is that the bullet is too heavy for the rifling twist he believes to be 1-14.

Any light shed on this would be appreciated. Or direction to a formula to help deturmine a good bullet weight for the rifling. They had this formula on a cable shooting show but he was not quick enough to write it down.

I know he's usin them dangblastid condomnated rounds but I figured someone here might be able ta help
Thanks

Only one cure, have him box it up and send it to me...

sorry, just had too. I've never played with a marlin 25-20, but my 94 in 357 mag is extremely accurate for what it is.

regards,
Graycg

Speer makes an extremely good 60 grain RN. I mostly shoot a Lyman 65 grain GC through my Savage .25-20. I have had 500 Rem 86 grain bullets for years, but have yet to load one for the .25-20.

[ 11-08-2003, 02:34: Message edited by: Leftoverdj ]

Sir: may I refer you to my posting to you on this subject in small calibers? ned

West Creek Charlie-

Sorry for the late reply - just cruising thru the posts here from the last few weeks.

FWIW - I've shot the WW factory loads also featuring an 86 gr. bullet and it shot well at 50 yds. <1" with irons. Has your buddy tried other ammo than the Rem.?

Just finished building a couple of CB loads - one using a 75gr. NEI design the other an 85gr. Old-West. Both shooting into <1" at 50 yds. During the process of load development - I did find the rifle/round to be very picky as to what powder it liked. For me - 2400 worked best with the 75 gr. bullet while AA-2015BR did the trick with the 85 gr. Other powders in similar burn rate range would shoot double the group sizes and more.

Regarding your question - Max bullet length for a given rifling twist is given by Greenhill's formula:

MIN twist rate to stabilize a given length of bullet:

T = 150 * [D/R]

MAX length bullet that can be stabilized:

L = [150 * D] / T * D


Where� T = twist rate in turns/inch
150 = velocity constant
D = bullet diameter in inches
R = ratio of bullet length/bullet diameter

For a .257 bullet - 1:14 twist bbl - max bullet length calculates as 0.708"

The 85gr. CB with GC attached is .698" long.

Best regards-

Sky C.

I am a big fan of the 25-20 round and almost bought one of those Marlin when they came out. The reason I did not was because Marlin used 1-20 twist rifling. These rifles shoot well with 60 grains bullets, but just won't stablilize the heavier weight bullets such as the 85. 1-14 or 1-16 is about the right twist..I don't know what marlin was thinking. I have looked at several of these used over the years, but have shyied away from them for the above reason.

Charlie....The Marlin 25-20 has a 1-14 twist. It will only stabilize the 86 grainers if you push them really hard. I was able to get 1 1/2" froups from an 86 grainer at 1810 FPS. I was happy until I saw that the bullets were tipping slightly at 100 yards.

Now, the 257420 Lyman which runs right at 70 grains does all right in it as the twist is fast enough to stabilize it.

I rebarrelled mine with a 1-12 twist and it now handles the 86-90 grainers just fine. Shouldn't have to do this to a factory rifle but what the hell, I wanted one./beagle

Beagle Ol Buddy..I am not trying to be argumenative BUT...I have a Winchester 92 levergun and a Remington 25 pumpgun both in 25-20 WCF. Both of these rifles have a 1-14 twist(industry standard for the 25-20) and I shoot 257312 (90 grains)at velocities between 1,400 and 1,700 fps and have never had any problems with those bullets not being stable, tiping etc.

I never measured one of the new Marlins, but I have a pretty strong memory about reading the twist was 1-20. It would not be the first time I read something in a gun rag that was wrong, but this one caught my attention because of my great fondness for the round.

Folks were getting great accuracy with the Marlin 32-20s, but the 25-20s were only doing well with lighter bullets and the slow twist was blamed.

Now..I am not going to argue with a fellow who has one and had it rebarreled..but my memory is pretty sharp on this point.

Whatever..the 25-20 is one great little round. I bought my first one (A Winchester 92) in 1960 and have not been without one since that time.

Sirs: the new Marlin classic .25-20 I bought in the 80's came with a tag reading 12 inch twist. It shoots Rem 86's well, Speer 75's well, 257420's well, didn't try 60's, and old Nosler 75 solid base hp's poorly. Never measured the twist, trusted Marlin. ned

Well G.ned...I just have to throw up my hands and say I don't have a clue what the twist was in those rifles...I think I will shoot off an email to Marlin and see if they know.

Charles...No problem...whatever it was is now a 1-12 and it will shoot the 257312 and the 257464 just fine. Before I was getting the tipping at high velocities and sideways at 14-1500 FPS out of the factory barrel. The 257420 shot all right but I wanted the heavier bullet and also a full length magazine so I corrected both the twist and the magazine problem at one whack./beagle

I'd trust a boolit caster afore a gun mag writer. ned