Mauser Caliber Ideas

[OntarioHunter]

Put on your big boy pants. Last summer I built this 404 Jeffery on an 8mm BRNO vz.24.
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Lilja made the barrel and Dennis Olsen put it on the action. Both are in Plains, MT. A local machinist here opened up the bolt face using Duane Wiebe's useful booklet for making these conversions. I did the rest of the work including installing a 3-position Model 70 style safety from Parkwest, 416 Remington bottom metal (trigger guard/magazine box) from Swift-Blackburn, magnum length follower from New England Custom Gun, Model 70 Safari Express iron sights from eBay, Timney trigger from eBay, semifinished stock from a GunPost vendor, scope rail from Sarco, and Warne Quick Detach rings from eBay. I also modified the action feeding ramp, rails, exctractor, and follower to cycle much longer and fatter 404 cartridges. The stock came with one recoil crossbolt and I added a second "internal" one behind the magazine box (a la Weatherby). And I floated the barrel and bedded the action.

I would advise upgrading to 375 H&H rather than 404. It's easier to find ammo and components for 375 which is also a more versatile caliber. These actions have been built into 416 Rigby (e.g. Harry Selby's rifle) but I think that's pushing the envelope ... for both shooter and the action. 375 is an excellent caliber for anything from deer to 1700 lb Cape buffalo. I used one to take two buffalo.
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Did I mention I've never built a big bore rifle before? It's not rocket science. Not quite.

Just finished upgrading my 404 Jeffery project with a used commercial stock I bought on line, a new 1-4x 30mm scope, and lower one-piece base. To beef up the stock for 404's heavy recoil I added croosbolts and a steel reinforcement rod through the wrist. The military action and Timney trigger had to be modified to fit the slimmer commercial stock. Then I rebedded the action and refinished the stock using Linspeed oil. Turned out well.

 

[6mm Remington]

I have a .338-06 and wish they made a good 200gr option. I use both the 185gr and 210gr Barnes TTSX

200 gr. Nosler Accubond
200 gr. Nosler E-tip

 

[CaliforniaPatriot]

375 ruger - do something crazy

My .375 Ruger is my go-to hunting rifle. Barnes TSX's, RL15, 1" groups or less when I'm up to the task. Averaging around 2725 FPS to my recollection; it's perfect for everything that isn't "true" long range (I'm good to go up to 300 yards at any time, could probably make 400 acceptable with practice).

 

[6mm Remington]

6mm Remington - 7x57 Mauser - 338-06

 

[OntarioHunter]

For a North American heavy hitter Mauser build, I think 35W is hard to beat. However, someone earlier described it as a "dangerous game" caliber. When speaking of dangerous game rifles (DGR), the term is usually applied to Africa, and over there that caliber would not be considered legal for dangerous game in most jurisdictions. 375, or in some places 9x62, is the minimum.

I am quite pleased with my 404J build on vz.24 but it's not a project for the faint of heart or wallet. I have $2300 into the project and did most of the work except barrel installation and opening the bolt face. Modifying the feeding rails, loading ramp, extractor, and follower is tricky. Building a 35W would be much easier and more economical. Bolt face, extractor, follower, and loading ramp should work as is. Rails and mag box MIGHT require slight modification but I suspect not. Possibly you might consider new bottom metal but not necessary. Nothing wrong with the Brno machined bottom metal. You may want to change the safety if you plan to scope the gun. I went with 3-position Model 70 style that included new bolt shroud ($200). Timney trigger with trigger block safety is somewhat more economical ($150). Or Buhler style scope relief wing safety ($75). I used a one-piece rail/base to accommodate existing 3-hole setup in the receiver. You might consider having a gunsmith get rid of the stripper clip port/hump for more conventional 2-piece bases. New barrel and installation cost me $1K. You could order a heavier barrel profile to fill the barrel channel in the stock you have. Barrel maker will sort that out for you. Good luck. Looking forward to hearing what you decide to do with grandpa's gun.

 

[MrCarbine]

May I suggest the 6.5x55 Improved. It is not that far behind the 6.5-284, if at all, and you don't have to alter the feeding rails. As a bonus you will maintain the 5 shot capacity.

 

[std7mag]

I've got a 35 Whelen Mauser barrel taking up shelf space..

Not to derail, but what other barrels do you have laying around?

 

[p_ham]

Not to derail, but what other barrels do you have laying around?

Mauser- 35 Whelen, 30-06, 280
I think they're all stainless though.

Tikka blued new take offs - 7 rem mag, 30-06, 308, 6.5 cm midweight

Tikka stainless- 308

Howa Mini- 6mm arc sporter contour

A few Marlin barrel in 30-30 and 444.

Also a .458 blank and a spiral flute 6.5 blank.

 

[ImBillT]

I'm all about the 7X57 AI also.
Once you try it you'll never go back.
Get it in a 1x7 twist and use the LOOOOG bullets.
The 8mm X57 has very few bullets to from, 7MM has old school, and all the NEW bullets.

Which 7mm bullets require a 7” twist?

 

[Forkyfinder]

Which 7mm bullets require a 7” twist?

.284/7mm 192gr SINGLE FEED MTAC (Match/Tactical) - 50ct

.284/7mm 192gr monolithic, solid copper match-grade projectile. This MTAC (Match/Tactical) bullet is a non-expanding, monolithic long-range bullet with a high BC, perfect for match and target use.

cuttingedgebullets.com

CNC mono metals

 

[ImBillT]

I personally lean toward something using a X57 case and not AI’d simply because it will not require any modification in order to feed.

6mm Remington if looking only to shoot deer and varmints.

6.5x57 would be my favorite. The shoulder is placed at the same location as the 8x57 giving it a short neck and 63gr H20 capacity. The 6.5Rob uses the 7x57 shoulder placement giving it a long neck, and under 60gr H20 capacity. The 6.5x57 will do anything a 6.5-284 will do, but will not require any modifications to your action or bottom metal to feed. Additionally, I’ve never found any 284Win or 6.5-284Norma brass that was of high quality. Use any 8x57 brass. Lapua, Norma and RWS are top quality. The only down side is die availability. I’m not a big fan or Hornady, but you might be limited to that.

7x57. Basically a cool version of the 7-08. Should be excellent for deer and elk.

AI versions of a 6.5Rob or 7x57 are excellent give a performance boost that is well worth the trouble in most actions, but they will likely require some efforts to achieve proper feeding in a Mauser action, so that’s an important consideration. My 6.5RobAI will essentially match a 6.5-284 or 6.5-06, but so would a 6.5x57 without requiring the AI modification. A 6.5RobAI and 6.5x57 both hold 63gr of H20. The 7x57AI will hold about 64gr H20, making it about equal to a 280Rem, but by no means equal to a 280AI. It will definitely out do a 7-08. The 6RemAI is unnecessary. The regular 6Rem already holds all the powder you need, and the shoulder is already sharper than the 7x57.

I’m not a big fan of 25cals simply because it’s so similar to 6.5mm but without the bullet selection. There are lots of good dies for 257Rob and 257RobAI. The AI version does experience gains similar to the 6.5RobAI, so it’s much more worth it than a 6RemAI, but of course, usually requires some modifications to get it to feed well in a Mauser. Nothin wrong with a standard 6.5Rob in a Mauser action. It’s a deer hammer. I’m sure people have killed plenty of elk with one. I would personally feel more comfortable using at least 140gr bullets on elk, which mostly cuts out .257” cartridges, but A) I’m no elk expert, and B) there are some very heavy .257” bullets if you’re willing to go out on a limb.

 

[ImBillT]

.284/7mm 192gr SINGLE FEED MTAC (Match/Tactical) - 50ct

.284/7mm 192gr monolithic, solid copper match-grade projectile. This MTAC (Match/Tactical) bullet is a non-expanding, monolithic long-range bullet with a high BC, perfect for match and target use.

cuttingedgebullets.com

CNC mono metals

So you would recommend getting extreme on the twist so that he can shoot a niche bullet that doesn’t expand and is marketed as match use only?

 

[Forkyfinder]

So you would recommend getting extreme on the twist so that he can shoot a niche bullet that doesn’t expand and is marketed as match use only?

Lol no way. A 1 in 7 twist 7mm is a waste.

 

[ImBillT]

Lol no way. A 1 in 7 twist 7mm is a waste.

Agreed. But I was quoting a guy that recommended a 7” twist.

 

[D4570]

Can't over-spin them. Who knows it 5 years what the bullet technology will be?

 

[ImBillT]

Can't over-spin them. Who knows it 5 years what the bullet technology will be?

Depends on what you’re shooting. It’s entirely possible to have too much twist. In five years buy a new barrel.