Marlin 1895 Guide Gun (18.5" bbl) and XLR (24" bbl) velocities for .45-70 Govt.


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1858
February 21, 2010, 04:12 PM
Here are the rifles used ...

http://128.171.62.162/hawthorn-engineering/thr/marlin/xlr_guide_gun.jpg

The velocity data was generated using a CED M2 chronograph approximately 15' from the muzzle. I had four rounds of a previous load leftover so I put two each through the Marlins as "fouling" shots and based on only four rounds the difference (average) between the two barrels was 63 fps.

http://128.171.62.162/hawthorn-engineering/thr/marlin/range_targets/02-20-10/chronograph_data_2.jpg

Lyman's 49th Edition lists the MAX load for N-130 and the 405gr JSP at 48.5gr. They used a 24", 1:18 twist barrel and managed 1,744 fps at 26,900 CUP. The Marlins have a 1:20 twist.

I shot five rounds through each Marlin using the load shown below making some scope corrections between shots. I then shot five more rounds through each Marlin with no scope corrections. Those two targets are shown below along with velocity data for all twenty rounds. Based on 20 rounds, the difference (average) between the two barrels was 72 fps.

Another 0.5gr for the Guide Gun could bump up the velocity to 24" barrel levels which might reduce the groups. Also, I don't shoot the Marlins very much so practice would definitely help and recoil is a hindrance to accuracy/precision. I still feel that the Marlins are capable of 1 MOA groups at 100 yards ... I just haven't managed it yet!! I need to make up a new target too. With a 5x scope, I couldn't get a consistent hold on the 1" red diamond. Also, I'm going to order a "sissy pad" this week to make load development a little more enjoyable!

http://128.171.62.162/hawthorn-engineering/thr/marlin/range_targets/02-20-10/chronograph_data_1.jpg

http://128.171.62.162/hawthorn-engineering/thr/marlin/range_targets/02-20-10/48.5gr.jpg

:)

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Baldeagle
February 21, 2010, 04:43 PM
Thanks for posting that. It's very informative. I believe that I just may go with the 1895GBL. Abel had posted a pic of said rifle on the other thread that I had started. However, for some reason the octagon barrel really draws my attention,With that being said, I think I can get one now(shorter of the two), and later down the road get the other...Again, Thanks for taking the time to post your findings.

1858
February 21, 2010, 04:53 PM
Baldeagle, you're welcome. I want a Cowboy version too at some point and I definitely wouldn't want to cut that 26" barrel down. I think it'd be more of a safe queen though so I'm in no rush to get one although I probably should while they're still available.

http://128.171.62.162/hawthorn-engineering/thr/marlin/1895/cowboy/1895_cowboy.jpg

:)

Ridgerunner665
February 21, 2010, 04:57 PM
You're right 1858...many Marlin 1895's do shoot MOA and below at 100 yards.

But its more commonly done with cast bullets and lapped bores.

Marlins are known to have constrictions in the barrels. At the dovetail cuts and at the front sight. Mine was no exception to this and I'd say yours is the same (95% of them are this way).

Maybe you knew this, maybe you didn't...but lap the bore and load some hardcast bullets sized at .460" and watch those groups shrink.

Baldeagle
February 21, 2010, 04:58 PM
I just may have to get myself a late Christmas present(now)... then in a few months get myself a great B'day gift :evil:...I have other rifles that I seldom use, I just can't bring myself to sell them to help out with my new wants.

Baldeagle
February 21, 2010, 05:00 PM
ok, I know this is going to bring out my intelligence. However, I must ask, What does Lapping a barrel mean?

Ridgerunner665
February 21, 2010, 05:03 PM
Lapping smooths the bore...removes tooling marks left during manufacture.

It also makes sure the bore is the same diameter from one end to the other....this is a MUST for shooting cast bullets.


It can done either by hand or firelapping...I hand lapped mine, but that takes a bit of "know how".

You can buy a kit to fire lap them from here (complete with instructions)... https://beartoothbullets.com/bulletselect/index.htm

iamkris
February 21, 2010, 05:04 PM
This is another example that says the "common wisdom" of 50 fps per inch of barrel is hogwash for some calibers and powders. You're showing < 15 fps / in.

I tested a 21" FAL and a 16.25" FAL once back to back. It worked out to about 20 fps/in.

Granted, not completely scientific as there are differences in chambers and barrels that can cause the velocity difference also...but still, that is a lot less velocity delta than most people would assume.

Ridgerunner665
February 21, 2010, 05:08 PM
Velocity loss...its very small in the 45-70 because of the expansion ratio. Put simply that means that due to the large bore size there is a lot more space for the pressure to occupy for every inch the bullet moves down the bore...the pressure drops QUICKLY, making barrel length a bit less important.

tango2echo
February 21, 2010, 05:10 PM
Great post. I have the 1895SBL guide gun. Your velocity numbers mirror mine with the same weight bullet.

Very interesting comparing velocities between the 18" and 24" barrels. Maybe we can get someone with the 22" barrel to chime in, as well as someone who has shortened their's to 16.25". I've been thinking of cutting mine down a couple of inches.

Mine shoots best with 59.7grs of H4198 and the 325FTX. Right at 2300fps from the 18" bbl and 1.5-2.00 at 100 yards.

I've had trouble with the rail coming loose from recoil, even with loc-tite on the screws. When I resolve this problem I will work on some other loads for accuracy. Dang thing kicks like a mule out of a 7lb rifle.

t2e

Ridgerunner665
February 21, 2010, 05:14 PM
I have a 22" 1895...but my loads are quite a bit warmer than 1858's.

Beartooth 405 grain LFN/GC
Remington brass
CCI BR2 primer
50 grains of H322
OAL 2.55"
Muzzle velocity is 1,886 fps (average for 10 shots)
Recoil is...stout (to put it mildly)

Thats not a MAX load (per Hodgdens online data)...but its on the warm side. Those bullets can be pushed 2,000 fps from a 22" barrel with H4198.

1858
February 21, 2010, 07:31 PM
I gotta say though, I'm shooting the Marlins prone since I don't like shooting off a bench. I think the prone position makes the felt recoil worse since the upper body (through the hips and legs) is kind of anchored to the ground. Off a bench, the upper body can move back more readily. Just a theory and I might be off on this one but my point is that I don't know that I want to shoot significantly stouter loads from this position but I'll see how it goes once I get a sissy pad.

Maybe you knew this, maybe you didn't...but lap the bore and load some hardcast bullets sized at .460" and watch those groups shrink.

Thanks ... I didn't know that. I did buy a box of 1000 Remington 405gr JSP bullets so it'll take a while before they're gone. I'll order some hardcast bullets from Oregon Trail or similar though. I just wanted to add that I'm only using N-130 because I got a couple of pounds of it for $19/lb. I'll be switching to more mainstream (easier to find) powders once it's all gone.

:)

Ridgerunner665
February 21, 2010, 07:35 PM
Those Remington bullets are hard to beat for the price ...I agree.

But you can get custom cast for about $20 per 50 bullets.


Beartooth and Jae Bok Young to name a couple...
Orgeon trail and similar may or may not stand the pressure of "full house" loads...with either of the ones I mentioned lubing or leading will never be an issue. If you have problems with either...its your barrel, not the bullets. (hence my suggestion to lap the barrel)

Beartooth 405 LFN/GC pictured here...LFN means long, flat nose. The bullet has a pretty fair BC.
http://i217.photobucket.com/albums/cc137/Ridgerunner665/132_3214.jpg

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