Hello there, I have a question for some of the folks on the forum. I have a kar98a that use to have a 220 swift barrel on it. I’ve asked questions about it before but I’ve taken a totally different path on the receiver. I sold the barrel and cleaned up the receiver as best as I can. My question now is would a 450 bushmaster barrel be an option for this receiver? It’s below what 8mm mauser ammo is rated for so I figured it would be safe. I have been watching Rhineland Arms as they have a screw one 450 bushmaster barrel.
The bolt face is the correct diameter for the 450 Bushmaster and that is not an issue. The issue that can arise is with cartridge feeding and there are solutions for this if it is a problem. The 450 Bushmaster to 98 Mauser swap is a viable and very functional and useful conversion.
I have done 2 98 Mauser barrel swap projects. One fed the 450 bushmaster cartridge flawlessly without modification and the other ended up needing a magazine conversion to feed reliably. I used the Rhineland arms Barrels on both of these swaps. Rhineland uses Green Mountain Barrel Blanks and the barrels are accurate.
I have switched to the Bear Creek Ballistics 450 BM Bullet for handloads in Bolt actions and other non-AR platforms which extends the COL close to a .308 length cartridge and I think these will feed much better in conversions. The Ballistics of their loading that I use speaks for themselves.
Attached is a pic of the first one I did on an Interarms Mauser 98 action and a detachable magazine that allowed it to feed properly as well as a 3 shot group shot with it. The Swarovski Z6 1 x 6 with Warne Bases and KenFarrell Rings works well with this combination. I have used the 450 Bushmaster for the last 2 deer seasons (8 deer) as well as a number of hogs. For 200 yard and closer hunting, which is mostly what I do, the 450 Bushmaster puts them down with authority and so far all have dropped right in their tracks.
The second 450 BM Mauser I did was on a new left hand Zastava Mauser 98 action which feeds flawlessly with no mods.
It is a cheap Hogue Pillar Bedded stock which handles like a dream, no mods, just glass bedded the recoil lug. The bottom metal is standard Military 98 Mauser, no mods. The magazine is a Gibbs type Mauser conversion magazine from Numrich for a 30-06. I ordered several of these for 30-06 rifles and they sucked so had them in a junk box. When I had feeding problems on the first project, I tried it with the 450 Bushmaster and was shocked it worked so well. Feeds the 450 Bushmaster perfectly but sucks with the 30-06, go figure. Where the 30-06 case tapers it acts as a cartridge guide for the extractor to positively clip to the bolt face and guide the cartridge into the chamber. Wonky looking but it works. For some reason, this particular action would not feed smoothly as I would have liked and I used the Gibbs Magazine to solve the problem.Keep in mind though, most have solved the problem with simple mods to their stock follower and sometimes a little tweaking on the action. There is no reason you have to use a detachable magazine and not having to worry about loose mags is nice. The only thing you should have to buy for the conversion is the barrel. You should be able to make everything else there work.
The Rhineland Arms barrels use the Savage style locking nut which is super simple to headspace and tighten it up. I bought a No-Go 450 Bushmaster headspace gauge from PTG to do this with. I have used Rhineland Barrels on 7 different projects (different calibers) with excellent results.
The KAR98a is a small ring short rifle dating to WWI. Not to be confused with GEW98 large ring of WWI or the K98k large ring of WWII. All 3 were 8x57. I am sure the OP understands this, becasue he properly identified the rifle in his post. I dont see why that this would be problem for the 450BM, but; maybe some difference in the barrel. Dont know. Seems most replies did not pickup or make mention of the gun. That could be due to the prior discussion which i did not read.
The KAR98a is a little bit on the special (ie. collectable) side of things. Then, anything German seems to be sought after.
Anything special about my Kar98a went out the door when the barrel was taken off the receiver. I purchased the rifle as just a barreled action. It’s been drilled and tapped for a scope mount as well. I had thought about putting it back into a military stock at one point I saw a kar98a kit that had everything but the receiver on gunbroker I decided to watch that but it jumped up in price to $755 last time I looked. I thought that was pretty insane so I went this route instead.
The KAR98a is a small ring short rifle dating to WWI. Not to be confused with GEW98 large ring of WWI or the K98k large ring of WWII. All 3 were 8x57. I am sure the OP understands this, becasue he properly identified the rifle in his post. I dont see why that this would be problem for the 450BM, but; maybe some difference in the barrel. Dont know. Seems most replies did not pickup or make mention of the gun. That could be due to the prior discussion which i did not read.
The KAR98a is a little bit on the special (ie. collectable) side of things. Then, anything German seems to be sought after.
The small ring 98 is a cool value proposition for a 450 Bushmaster conversion. I believe Rhineland Arms sells more small ring mauser barrels than the large ring mauser 98 barrel.because cheap small ring mauser Non-98 actions are available. There are a lot of Non-98 small ring 93-96 mausers converted to 450 bushmaster due to its low 38,500 psi level. The fact that the Kar98a is a small ring should not be a problem for this conversion.
Parts can be crazy. These days anything can be crazy. Fixing/restoring something for 2x what it is worth never made sense. I fell into that trap a few times. I know, you know about the KAR. I was not sure the others knew. I am no scholar of the Mauser, but; I do have a KAR98 which is why I got a bit educated on this model. Then again, I never got into it like you are. I simply " do not know " all the details of differences inside the KAR version. It seems more or less a whole different gun. Apparently a barrel swap is all the same. No surprise.
I have a 450 BM in a Ruger American and expect it should make a fine brush gun on deer with a little more distance and punch than the old 44mag. I have not begun reloading for that. I am at the mercy of the wizz bang red tip bullets. I miss the simple times, when ammo had round nose exposed lead like the old 35 Rem. On paper the 450 looks like a winner.
A friend of a friend sent his Ruger back due to some feeding issue. I guess that worked out in the end and might tie in with some cautions already posted. Again, I dont know and perhaps should leave that to those who do.
Fourbore, for sure building a military action-based sporter, is a hobby and a passion, not something you do to make money.
Those Ruger Americans in 450 BM have developed a reputation for excellent accuracy. The Hornady Black Box with 250 grain FTX bullets is hard to beat on the accuracy side even with hand loads.
I know this is an old thread, but it was very helpful to me and I thought I would add my experience to perhaps help others. I just got finished converting my german Mauser 98 to 450 BM and as others suggested it is indeed a very doable project. The action was a barreled action in 257 roberts I picked up years ago on gunbroker. A new bolt handle had been welded on as well as a nice latched floorplate conversion, but other than that the entire barreled action was in rough shape, but some TLC and rust bluing fixed that. I inletted the entire thing into a custom walnut blank myself, it was my first time doing this and while its not 100% I learned a lot and its something I am very proud of. It would never shoot well and ended up spending most of its life in my safe until I started research the 450BM conversion and found this thread (and others). I ordered a 450 barrel blank from X-Caliber and had my gunsmith thread and install it. This was then re-inletted into the walnut stock. It turns out that the magazine box was binding a little on the action and this was perhaps why the 257R never shot well, but that was corrected this time around. I wasn't lucky at all when it came to getting the cartridges to feed from the magazine. As is, they wanted to nose dive in the magazine box and if I nudged them up with my finger they would end up binding in between the feed rails and not popping up on top. I tried the detachable magazine FSJeeper suggested. Initially it wouldn't fit into my magazine box, after a little modification it would but feeding was gritty at best and controlled round feeding was hit or miss. Plus, I would have to do away with my latched floorplate. After I little tinkering I found that if I used a short-action follower and spring from my 1990's era Rem 700 and loaded the cartridges towards the back of the magazine well (but not all the way back) they would start to feed well but hung up a little at the 98 feed ramp. I purchased a new production Rem 700 spring and follower from a member on here, trimmed about 1/4 inch off the front of it with a dremel, and installed it towards the back of the magazine box. At the front of the magazine box I fitted a UHM plastic block as a spacer, the top of his block I tapered with a rasp so that it acted as a pre-feed ramp of sorts. Cartridges fed perfect after this, except for the very last cartridge which I needed to place a bead of JB weld on the follower to move that cartridge a little more to the center of the magazine well and then it fed. I didn't have this problem with the 1990's follower, just the new production follower which was shaped a little different. This is my second X-caliber barrel, both are very accurate and I am looking forward to testing this one in deer gun season.
