When I got home, the gun had to be rebuilt with stronger screws, replacement springs, etc. We just pushed that little carbine too far.
@Green Chile , over the years I have heard many a tale about some of these lever guns being pushed way way too hard, I commend you for knowing what you were doing, and admitting it afterwards. So many do it, and claim it to be common practice..........
I have a couple of 51 Alaskans. .510 caliber. I did a Marlin as well, and a Ruger #1. I have shot the #1 far more than the Marlin.
Just after I had those done, I created the 50 B&M Alaskan..... .500 caliber. Take Starline 51 AK squeeze it down to hold .500 caliber. I did this back in early 2007. There are two lever guns that can be easy converted to either 51 or 50, the Marlin as mentioned, and the Winchester/Browning M71s that came in 348 Winchester. I did both, the first 50 B&M AK was a Guide Gun converted, and a Hi Grade Browning M71. Later I did a Marlin pistol grip version, that is far superior in handling recoil than the Guide gun version. Similar to the M71s.
In those early years, I was very busy with the various B&M Bolt guns, too much to do a lot with the lever guns at that time. There were far more .500 caliber bullets available that would work great with these cartridges than there was .510 caliber. To mention one, the 500 gr Hornady Flat Soft Point. I quickly just put together a load for this Guide gun running the 500 Hornady at 1950 fps, the gun worked fine, all is good, and put the project to the sideline for the time being.
I had this Marlin Pistol grip version done, but had not fired it or messed with it at all. Then the Hi Grade Browning M71 which I was also shooting the 500 Hornady at 1950 fps or so...... all good.... UNTIL......
Layne Simpson loves lever guns, through JD Jones he learned about the 50 B&M Alaskan and wanted to do an article on them. So he touched base, and I was going to send him the Pistol Grip Marlin and one of the M71s for him to play with and do the magazine Article. Before sending, I thought maybe I should shoot the Marlin a few times before sending, make sure there was no issues. Well that same 500 Hornady at 1950 fps that worked so good in the Guide Gun, LOCKED Up the Pistol Grip version tight! Ooppps........ Not good! So I got busy, loaded down to 1850 fps and sent Layne the guns for the article....... All worked great.
All lever guns are not created equal. That Guide Gun handled much more than the Pistol Grip version. When I got the rifle back, I put a strain gage on it, and started working up loads and getting real pressure data.
You want to keep the Marlins at or around 45000 PSI, the Browning M71s can handle just a bit more at or around 50000 PSI. If you go beyond that over the long haul you will end up with some issues.
BTW, all my Lever 50 B&M AKs are 18 inch guns. I could run the 500 Hornady to 1873 fps at 45200 PSI, I backed it down to 1842 fps for 42000 PSI....... In the Marlins.
Layne and I did a good bit of load data in the 50 B&M AKs, he also had a musket built in 50 B&M Alaskan at 22 inches with a laminated stainless Marlin, this is Layne's rifle;
It was 2011 before I went to the field with the 50 B&M AK, and by that time we had designed some special bullets for the mission at hand. We developed a 405 gr Lever Solid at CEB and a matching 365 gr Lever Raptor. I used one of the Browning Hi Grades running the 365 Lever Raptor to 2175 fps and the 405 Lever Solid to 2120 fps. The Solids were Impressive. I did not take elephant, but the cartridge, rifle and of course most important, the BULLETs did a number on hippo and buffalo. Not to mention these guns are FAST.........
We developed several bullets from CEB and North Fork for these rifles and they proved to be very capable.
Of course I still have the 51's....... and wanted a bullet combination for them as well..... so I had CEB do a 350 gr Raptor and 400 gr matching Solid in .510 caliber...........
And to be honest, I never ordered any 400 Solids and never tested them. Since I would never take a .51 to the field I never took the time. I am 100% sure the 350 Lever Raptor and 400 Lever Solid in .510 caliber would perform the same as the .500 caliber versions.......
If you had a 51 AK, it would be to your advantage to look at the 350 Raptor and the 400 Solids, depending on your mission.
Don't get confused between .500 and .510 either......... LOL