I want to build a 500a-square on my Ruger mk 2 rsm in 375h&h, My gunsmith thinks it possible,but he posted Ruger to be sure.He has'nt got an answer from them yet(2 monhts) So my question? Is the action strong enhoug for the pressure of the 500a-square? (Pardon my english)
ALLAN, I am not sure which Ruger rifle you are talking about. But if it is their Express Magnum action that they use for the 416 Rigby, then you will not have any problems building a 500 A-Square on it.
I find your comment about the 375 H&H being a low pressure round curious. I don't have load manuals handy, but believe the 375 is rated to as high a pressure as any modern round, or at least within a few kpsi.
I've seen several 505 gibbs built in the ruger M77 mag action, should be no probably to put a 500 A-square in it.
Posts: 7213 | Location: Alaska | Registered: 27 February 2001
Allan, It is much easier to build a 500 Jefferys on that action, much less labor involved particularly makeing it feed and since you can seat the bullets out with the Jefferys, you can get some real velocity, for whatever thats worth if anything....I just think there are a lot better designed 50 cal. cases around than the A-Sq. just my opine however......
Paul H, You are right. The .375 H&H is indeed NOT a low pressure round. Check it out 500grains and let us know. 52,000 CUP is my recollection, off the top of my head. Is that about 60,000 PSI?
Allan, I disagree with Ray. The practicality of the .500 A-Square in brass availability, as Norma .460 Weatherby necked up and fire-formed, plus other properly headstamped brass, makes it the most viable fifty. It is like an overgrown .458 Lott in its practicality.
If you want to use the Ruger 77, then you want to start with their .416 Rigby. There will be no bolt face alteration needed, and it will likely feed well with little or no work except reboring and rechambering.
------------------ Good huntin' and shootin', Bwanawannabe, Daktari Ron
The 500 Jeffrey is a great cartridge. But I have to agree with RAB, the 500 A-Square will easily push a 600 gr. bullet to 2400+ fps. which is all the power you will ever need. Plus with a reasonably priced plentiful supply of good quality brass available that makes the 500 A-square the best choice in my opinion. My 500 A-Square feeds great, plus you never have to trim your cartridge cases with the 500 A2. At least I have never had to after 7 years of owning one.
Thanks for your answers.The reason why i want to build a 500 on my Ruger is that i think it is to big and heavy for only 375
quote:Originally posted by Allan: I want to build a 500a-square on my Ruger mk 2 rsm in 375h&h, My gunsmith thinks it possible,but he posted Ruger to be sure.He has'nt got an answer from them yet(2 monhts) So my question? Is the action strong enhoug for the pressure of the 500a-square? (Pardon my english)
Hi Allan, Best ask your gunsmith about the cost to all the modifications to your Ruger to make the 500 A-Square. I started with a Bruno 602 action in 375 H&H for my 500 A-Square. It takes a lot of modification on the feed ramp and on the rails to make it feed properly and the magazine box on the Bruno is long enough for the 500 A-Square. I don't think that you'll find that true with the Ruger. They seem to make all their magazine boxes to the spec OAL of the cartridge chambered. If you are planning to have the barrel rebored to 50 caliber be sure to check with the success rate with Ruger barrels the person you are having do the work with has had. Cliff LaBounty did a great job with my 470 Mbogo but wasn't available for a second 470 we wanted to do on a Ruger #1. We sent it out to another re-boring company that was recommended and the barrel was ruined. He said the barrel was hardened to different tollerences in the throat and muzzle areas which caused chattering while boring. I know that Cliff has a list of barrel manufacturers who's barrels he won't work with due to the properties of the barrels they manufacture. You might be better off to find someone to flute your 375 barrel to drop some of the weight. It will make a big difference in the balance and it is a great cartridge. The 500 A-Square project may be better started off with a more suitable action that won't require as many modifications such as the CZ550. As far as pressures the 500A-Square works at a max pressure of 55,152CUP or 63,860 PSI and the 375 lists at 53,000CUP or 62,000 PSI the same working pressure range as most modern cartridges. 470 Mbogo
I have allready got a price from my gunsmith,and i think it is a fair price.The magazine box is big enough,but there is not much space left,so he will make it a little bit longer.I will change the barrel with a Duglas barrel.I was thinking about 23" long and 1-10" or 1-12"
Allan, Good choice on the barrel length and twist rate. With that you can get good accuracy from 570 to 750 grain bullets. A screw-on muzzle brake will make plinking with milsurp .50 BMG bullets more relaxing. I have a 23" McGowen barrel with one in 10" twist and it is the cat's meow IMHO.
