Thanks guys for the above info, so here are my new
Observations on the Marlin-Remington Guide Gun
6/4/2015,
by Marlin Leverguy
I just got a slightly used Stainless, 45-70 Marlin Guide Gun. It is marked Marlin, etc. on the left side of the barrel, but has a REP(f) Remington proof mark on the right side of the barrel. I believe the Receiver is Remington because it has the Serial number 9180xxxx on the left lower side of the receiver as well as on the receiver just below the bolt cavity. It also has a scan code block next to the serial number in the bolt housing (ugh) and the last three numbers of the serial number are also electro-penciled on the bottom of the bolt. Considering all those numbers I wish I knew what year it was made.
The stock of this Guide gun is nicely figured, dark walnut with fit and finish the same as old Marlins, except it has pressed-in checkering. The external metal work is comparable to slightly older JM production 1895’s, but the bolt has no fluting, it is smooth. However, my main serial number is punched in so hard it has sharp edges! The barrel crown is changed from the dual, deep radius on old Marlins to a deep radius on the outside of the barrel but practically no internal bore radius (it is more like a cone style crown). This is not a good change as it makes denting the muzzle much more likely (I will re-crown this one). Internal parts have considerable sharp edges with no attempt to hand finish them. The use of a little 400 grit paper removed any sharp edges on the internal parts and helped the trigger slightly.
Accuracy and reliability are good, I ran about 120 rounds through it in the last few days with one of my standard loads: (31.7 gr Alliant Reloader #7, 1504 fps @ 15 feet { 45.8 fps Standard Deviation, sample size 5 rounds} as tested in my JM 22”barreled 45-70 rifle). I would expect slightly lower velocity in the Guide gun due to the shorter barrel, but I did not run that test yet. The load used mixed Winchester, Starline and Remington once fired brass with a 300 gr cast lead plain based, flat point, truncated cone bullet and Winchester primers. This load is mild and I use it in original Trapdoor rifles. Accuracy was 1” to 1.25” groups at 50 yards with open sights.
Only one complaint, the detent safety button on the lever (which locks the lever in place for firing) was very rough. This resulted in considerable force being required to close and open the lever on firing and ejection. It appeared that the hole for the detent was machined rough or that the detent was rough, or both, which caused the lever to be hard to get into and out of full battery. Some file work and oil helped, but the defect is manufacturing, not design. It will not smooth out with use but needs a little intervention to be right.
Is the new Marlin as good as the old? Internal parts are rough, the serial number needed a sanding to take off sharp edges, but the manufacturing defect in the lever was the only real flaw. I think the crown should be redone as it was in the old Marlins, because it has better field function, but other than that the gun seemed ok for use. Time will tell on other fit and function issues. Once the lever is fixed and I run a couple hundred more rounds through it, I will be using it in Alaska for big bear protection.