Lot's of great discussion on this thread: Caliber to fill a gap...

I don't want to rehash the all same stuff, but I'm trying to make a similar decision and wanted to outline my thinking and get some feedback without hijacking Brian564's thread.

I thought I had it narrowed down to 257 Bob vs 22-250, but I flip flop between the two, and I would still consider another if there were good reasons given.

I'm not counting ballots to arrive at a decision so please, don't simply cast a vote with what caliber you would pick, or reply "+1". What I am looking for is feedback on my rationale for picking or not picking one over the other, and opinions on whether my concerns are valid or not.

First, a couple caveats: I intent to build it on a Mauser 98 action because I have several already to choose from. Like Brian I would like a flat shooting, high speed, light recoiling small bore rifle for paper, tin cans, and varmints. While I might choose to reload for it at some point, I want a common factory chambering where ammo is available and reasonably priced.

While most of the choices would work, I don't care about suitability for deer sized game. If I am hunting deer I will grab my 30-06, or a 7x57 that I intend to build in the future. If it would work in a standard Mauser action I would pick a 223, because everyone should have a 223 and I don't. ( I agree with "jfromswk" on the other thread) But it won't work, so I'm looking for the best small bore for the action.

On to the contenders:

257 Roberts - Pros are that the cartridge is a perfect match for the action. Taper, shoulder, etc. mean it will feed reliably and slick as snot. Cons are that factory pressures put the performance lower than what I would hope for. I could hand load, or bump it to an AI, but again, hoping I don't need to.

22-250 - Zippy performance, but concerned that the shorter cartridge may not feed as reliably. Is this founded? Is taper similar enough to standard Mauser cartridges that the shorter length doesn't matter? I'd rather not put a spacer block in the back of the magazine, but would consider it if that is the CW on the best way to make it work.

On to others I have considered, but are lower on my current ranking with reasons given:

243 - Seems to be a popular favorite, but concerned about the shorter, less tapered .308 based cartridges not feeding as well. Same goes for 7mm08.

25-06 - Seems like this would be a great round, although kind of overkill for what I'm trying to do with it. Only other concern is that my current 30-06, because of the longer shoulder, doesn't feed quite as slick as the 8mm and 7mmx57s that I have in an unmodifed Mauser action. Reliable, just not as slick... I do also have a .35 Whelen though, so maybe I should keep it in the family(?).

6.5x55 - I already have one, albiet in a short barreled carbine, and I will probably gift it to my nephew anyway. Similar to my concerns with the Bob, I'd like to get a bit better performance with factory ammo.

260 Remington - Never really thought about this one I guess...

I know there may be other good choices I'm missing. I know there's probably some eye rolling because a lot of this has been covered. I just needed to get it out of my system because it is haunting my thoughts... If you said your piece on the other thread I don't need you to repeat yourself, but if anything I said in my caveats makes you think of something fresh then please share.

Thanks in advance for any inputs.

I just did a Bob on a Milsurp K98. Like the caliber but haven't taken anything but a coyote with it so far. The only modification was to use a commercial follower because it didn't want to feed with the original.
Chose the Bob because I was looking for a light deer and varmint caliber and didn't want to have feeding issues. I reload so don't care what factory ammo does.

Had sort of the same situation many years ago, wanted a Mauser in something smaller. I settled on the 6mm Rem. works great as it is part of the
x57 family, good choice IMHO, still have the rifle
some 40+ years later. --- John

I have had an love affair with the 257 Rbts for about 35 years now, all most as long as the 35 Whelen. Those two calibers will do anything you want to do in North America

Am working on my hopefully last Rbts, 1910 Mexican, all surface ground, with an shortened, 1909 guard, Burgess bolt handle, PME three position M70 safety, and a Timey trigger with a # 2 Shilen barrel in 24". Still have to make the 1/4 rib, and ramp front sight. Then onto a nice piece of English walnut.

My other small caliber choice would be a 223 Rem on a M98.
Some say it can not be done, well they simply do not know how to do it properly, and that takes a new machined extractor, and remachine the bolt face. A new magazine insert in the old guard. results in a easy feeding 223 on a full size M98. The only draw back is the full length bolt stroke.

Yes I have done many of them in the past

Just my 2 cents.

J Wisner

Have a look at the hornady super performance loads for the bob !
...tj3006

For a 98? Yeah the .223 is out. Likewise short rounds like the .243 and .22 250. A 57 mm case like the 7 57 or 8 57 ought to fill the bill. The Bob of course derives from the 7x57. And you've been dancing all around the obvious conclusion. Neck down the Bob another step and you have the 6mm / .244 Remington. All the ballistics of the .243, IMHO a much more docile and consistent cartridge to reload, able to carry most of the Roberts' bullet weight and still use lighter bullets if you like. A bit too long for a short action with properly seated bullets (one of its downfalls when produced by Remington who seemed to hamfist just about everything about this excellent round) but just about a perfect fit in a long action, especially a 98.

Hhhhmmmmm.... That 6mm Remington looks very interesting.

Well, you might have a bit of availability problem with factory ammo since it isn't a red hot popular cartridge these days, but it is out there, and in a pinch you could make brass from .257 or 7x57 although you might have to turn necks. It is also popular as an AI, although I personally wouldn't bother. You might get an extra 200 fps or so but I've found that accuracy tends to decline a bit when you exceed the regular 6mm velocities. I build rifles for people and this has been my experience. And the fire forming can be a pita when you just want to shoot.
I feel that the 257 Roberts could just as easily have been a 6mm if the .25 caliber hadn't been so popular at the time. Now however you have a better selection of 6mm bullets so that might be a better choice. And barrel makers have developed 6mm barrels to a high art due to their almost exclusive use in benchrest. So yes, give it some thought. You might really like it.

Readily available over the counter anywhere limits things to .22-250, and .243. If you will reload then it really opens the field. I would then recommend the 6mm Rem, .257 Roberts, 260 Rem, .250-3000 Savage as my preferred choices and throw in the 6.5x55 and 6.5x57. The little Savage round could be used to make a really lightweight and very handy little rifle that would be a pleasure to carry but any of those cartridges would do for your project, except be readily available at Mom and Pop's Country store.

Jerry Liles

I guess I should clarify "readily available"... I didn't necessarily mean any mom & pop Beer/Ice/Bait store that sells 22LR, just that I could go to a reasonably sized sporting goods store and expect to find a factory offering (or two) at a price comparable to other centerfire rifle ammo.

Just to clarify, .243, .244, and 6mm are all the same bullets, just different naming conventions?

A 6x57 at modern pressures looks very promising.

6x57 is another name for .244 or 6mm Remington. Which is basically a necked down .257 roberts which was a necked down 7x57 Mauser which was a necked down 7.92 (8MM) Mauser. Of the commercial 6mm offerings it was Warren Page's favorite. He liked it uch better than the .243 Winchester.

A couple questions:

Would a 6mm Rem reamer clean up a .243 Win chamber? What if the .243 was "short chambered"? (the obvious follow-on: "that depends on how much it is short!") In case it isn't obvious why I ask, there's not a lot of pre-threaded pre-chambered Mauser barrels in 6mm Rem, but they can be had for the 243. I guess I could set it back a bit further as needed...

Twist rate: I've read about history of the .244 vs 6mm and their 12:1 and 9:1 respective twist rates. The 243 barrel from Shilen comes in 10:1, ER Shaw offers them in 8:1, 10:1 & 12:1. I would probably be shooting more of the lighter stuff at longer ranges so I don't see a reason to go all the way to 8:1, but in case I wanted to use heavier bullets I wouldn't want to duplicate Remington's headaches with the .244. I'm thinking 10:1 is the best bet. Any disagreement?

The standard 6mm Rem reamer will not clean up a .243 chamber but the 6mm Ackley will. Been there done that. No matter if short chambered. Don't let that be the overriding factor in your decision. The Ackley is still a pita and a lot more work. If you're going to diy, you might want to reconsider. Just get the 6mm blank and have a gunsmith chamber and fit it.

Get a 1 in 9" twist and don't look back.

quote:

Originally posted by H47:
Get a 1 in 9" twist and don't look back.

I'm not done looking yet, but my point is that so far I haven't found a 9:1 in an aftermarket barrel. If I had to choose between 8 and 10 I was leaning towards 10...

I'd like a good quality, accurate barrel, but it doesn't have to be premium because I don't expect BR accuracy from a Mauser.

So far I've looked at Shilen, Green Mountain, Wilson, and ER Shaw. I'm familiar with quite a few others, but will take suggestions.

When I did mine, many years ago, I used a Douglas
Sr. XXX premium barrel in 10:1. They were about as
good as one could get at the time. Quite a few others on the market now, get the best you can afford and you will be happy, JMHO of course --- John

Well I tend to use up - line barrels like Hart or Krieger. I also like Douglas. I put a lot of work into them and saving a couple of dollars by using a cheap barrel just makes no sense to me. And good or bad i get blamed for it so I like to s start with the best i can. Douglas make a very straight and well finished with(interior) barrel that should shoot quite well. I just finished one in 9.3 X 62 (yes I know it's out of your caliber range) that did a .565" 5 shot group at 100 yards. I was impressed. If you deal direct with the maker I can't imagine you having trouble finding a 9 twist in a 6mm. But if it came between an 8 and a 10, and you intended to use 105 gr. Vld bullets for example then get the 8.

I had the same problem a couple of decades ago: a Mod 98 action and I wanted "your" rifle.

I went for a 6mm Rem built by Dan Dowling using a Gary Schneider SS barrel with a Fajen stock. I opted for a 24" barrel with a 1:12 twist precisely because I wanted it optimized to shoot light bullets at targets and small varmints.

I got what I wanted: just today, I shot at 100 yards a 3-shot group that was 0.255 inches with a 55 grain Nosler BT (my best 3-shot group ever measured ~ 0.08 inches).

The rifle is very accurate with bullets up through the 87 grain Hornady. But it keyholes any bullet that is longer.

The problem with the 6mm, at least for you, is that most of the factory ammo (when it is available) is 80 grains up. That's not ideal for varmint hunting.

So although the 6mm is technically a factory round, and it is a superb cartridge that would seem to be ideal for you, it might not be suitable for you given that you are not ready to hand load and that there is a dearth of factory ammo (especially with lighter bullets).

My first choice would be 6mm Rem. with at least a 10 twist. As already said 8 or 9 for the VLD bullets over 100 grains.
The other choice would be a 22/6mm wildcat. There are a few different choices, depending on what case configuration. The straight just neck down to 224 is the easiest. The 224 Clark is an improved case with a 30 degree shoulder gives less feeding issues than the 40 degree AI version.

have you considered the 250 savage ?

quote:

Originally posted by craigster:
have you considered the 250 savage ?

I myself hadn't thought of that . . . while I think the 6mm Rem would be ideal if one is a hand loader, perhaps the .250 Savage would be perfect if you must have factory cartridges ("perfect" assuming that light-for-caliber bullets are available in factory cartridges, and that you don't want a .243).

Good idea.

Seems like an easy choice. The .257 Roberts is very versatile and fills the gap you described nearly perfectly. With a 24" barrel, you can shoot 75 grainers at 3550 fps and 87 grainers at 3450+.
Decide you want a low recoiling but effective deer or pronghorn rifle? Go with 100 grainers at 3100+. Might run into an elk or black bear?Go with 115 to 120 grainers at 2990 to 2950.
No sweat, no strain.
The .257 Roberts fills your gap much better than the 22/250. Plus which, if you keep the standard .257 chambering, they sell fast. The AI version...not so easily.

quote:

Originally posted by steyrsteve:
Seems like an easy choice. The .257 Roberts is very versatile and fills the gap you described nearly perfectly. With a 24" barrel, you can shoot 75 grainers at 3550 fps and 87 grainers at 3450+.
Decide you want a low recoiling but effective deer or pronghorn rifle? Go with 100 grainers at 3100+. Might run into an elk or black bear?Go with 115 to 120 grainers at 2990 to 2950.
No sweat, no strain.
The .257 Roberts fills your gap much better than the 22/250. Plus which, if you keep the standard .257 chambering, they sell fast. The AI version...not so easily.

Those are factory loadings?

quote:

Originally posted by craigster:
have you considered the 250 savage ?

Honestly I had not. Looks like a decent round. What are the pros and cons of the 250 vs the 22-250?

I have a 6mm rem built on a k98 action. this gets my vote.

The 250 Savage is my all time favorite light caliber, but IMO one should stay with a round that fits the action, A Mauser works best with a 7x57, 257 Robts, or 6mm Rem...I know you can convert them to 30-06 etc and even 404 Jefferys but the three mentioned have always worked best IMO...If I were to convert a Mauser to a 250-300 I would cut and shorten the action to fit, make a Kurz Mauser so to speak, that would be an awesome conversion with a small ring action, but damn its costly..

quote:

Originally posted by Atkinson:
The 250 Savage is my all time favorite light caliber, but IMO one should stay with a round that fits the action, A Mauser works best with a 7x57, 257 Robts, or 6mm Rem...I know you can convert them to 30-06 etc and even 404 Jefferys but the three mentioned have always worked best IMO...If I were to convert a Mauser to a 250-300 I would cut and shorten the action to fit, make a Kurz Mauser so to speak, that would be an awesome conversion with a small ring action, but damn its costly..

My 250 is built on a 1936 Mexican, no problemas.

I am surprised nobody mentioned the .240 Weatherby. It's a great fit for the M98.

I love the idea of a 6.5x57 because of the history, but obviously your stipulation of "factory ammo" makes that impossible.

You didn't say I couldn't dream aloud.

Between the 22/250 and the 257 Rob? The 6mm Rem. gets my vote on the mauser action, but nobody has mentioned the swift? Not exactly ammuntion central in most gunstores, but might warrant a cursory examination.

I heard that 6.5x57mm RWS ammo/cases were not up to standards. sold my blaser in that caliber.

quote:

Originally posted by Bren7X64:
I love the idea of a 6.5x57 because of the history, but obviously your stipulation of "factory ammo" makes that impossible.

You didn't say I couldn't dream aloud.

This is an interesting discussion of course with a lot of good ideas presented. Most of the calibers discussed will work, some perhaps a bit better than others, but all represent workable solutions. Your desire not to hand load right away along with your preference for something pre chambered complicate things a bit but not insurmountably so.

What seems to be happening at this point is that everything is getting hashed and re - hashed to the point where nothing new is really getting established. Any cartridge is going to a compromise so there will be no one single "best" in the last analysis. It's going to boil down to what "you want." I know people who can literally agonize over this kind of thing for months or years, finally make a choice and then maybe in a matter of weeks, think they ought to have chosen something else.

It's only a gun! Build it, shoot it, and enjoy it. You can always rebarrel or get another. It doesn't have to be the last one you'll ever get. Have fun. Experiment. Enjoy. Loosen up.

i have roughly the same plan for a 98 action i have. i have decided on the 6mm rem with the barrel twisted fast enough and throated for the longest vld bullets. even with a rifle set up for "normal" bullets, i think its hard to beat the 6mm rem for your purpose. good luck with your project

H47, Well said last post, and thanks for your original suggestion of the 6mm. That is now at the top of my list. 57mm standard taper Mauser case, modern pressure, impressive ballistics. Now I just need to pop into some local sporting goods stores to get a feel for availability and price of ammo. Nothing final yet, I have some competing projects, and may still look into Weatherby offerings.

Thanks to everyone else as well for the suggestions, and patience rehashing what often feels like deja vu all over again... Cheers.

Montea6b, just in case of any possible lingering thoughts, I meant no offense in my last post. I and apparently several others agree that something on the 57 mm case might work out best for you. You will likely feel better once the choice is made and you commit to the project. At least I hope so. And I wish you luck and all the pleasures something like that brings.

quote:

Originally posted by H47:
Montea6b, just in case of any possible lingering thoughts, I meant no offense in my last post. I and apparently several others agree that something on the 57 mm case might work out best for you.

None taken whatsoever! We are totally aligned in our thinking.

It was time to start wrapping things up, and therapeutic for me to talk it out. Thanks again.

quote:

Originally posted by H47:
...something on the 57 mm case might work out best...

The original 57mm case length is great for fitting the M98 action but when you go to smaller calibers aren't cartridges based on the .30-06 length case actually a better fit?


These are close to the original Cartridge Overall Length

8x57 Mauser = 3.228 in

.25-06 = 3.250 in

.240 Weatherby = 3.100 in

But these are much shorter

.257 Roberts = 2.775 in

6mm Remington = 2.825 in

.

I think the shoulder location affects feeding more than OAL.

Well I'm no Mauser guru and I didn't sleep in a Holiday Inn last night either. But if you use magazine length as the deciding factor then you're correct. However if you look at the feed rails in the receiver they are milled to a certain configuration with a little "hump" configuration toward the front. I think this is meant to engage the cartridge shoulder as it moves forward and line the cartridge up with the chamber. Since the shoulder on the 30-06 etc is farther forward, this part engages too soon and shoves the round too far left or right causing the bullet to stub on the back of the chamber. I suspect this is magnified with larger diameter bullets. But nonetheless it's likely that a 30-06 based round might need the feed rails altered whereas a 57 mm case as originally configured might not. Just a thought anyway...

I've had a few Mausers turned into full-blown customs and I love the 257 Bob and 6mm Rem. However, both cartridges deliver the full range of their capabilities in the hands of a reloader. If you look at the available factory loads, both rounds come in only 100 grain+ configurations which might be a bit heavy for your intended purposes.

If you're going to sink the required money into a custom Mauser, I'd go with a 6mm Remington and start hand loading. I've owned three and they all were extremely accurate and deadly on varmints and deer. If you go this route, I think you'll love it for varmints and find the rifle encroaching on your 7X57 and 30-06 in terms of deer hunting.

quote:

Originally posted by ForrestB:
I've had a few Mausers turned into full-blown customs and I love the 257 Bob and 6mm Rem. However, both cartridges deliver the full range of their capabilities in the hands of a reloader. If you look at the available factory loads, both rounds come in only 100 grain+ configurations which might be a bit heavy for your intended purposes.

If you're going to sink the required money into a custom Mauser, I'd go with a 6mm Remington and start hand loading. I've owned three and they all were extremely accurate and deadly on varmints and deer. If you go this route, I think you'll love it for varmints and find the rifle encroaching on your 7X57 and 30-06 in terms of deer hunting.

+1 (Though I believe you can buy 6mm cartridges loaded with 80 grain bullets over the counter.)

The only issue I'd bring up is barrel length and twist rate as it relates to purpose. If you're going to be perfectly happy shooting light bullets (≦ 75 grains) for high-velocity varmint shooting and paper, consider a 24 or 26 inch barrel and a 1:12 twist. If you think you might be shooting deer fairly often, consider a 22 inch barrel and a 1:10 twist.

But I'm assuming that with all the suggestions here, you've decided you just must . . . MUST . . . reload for this rifle!

Just to be clear, I am not against hand loading. I understand it is the best way to wring max performance out of any cartridge, but I just don't want it to be necessary in order to overcome some anemic SAAMI limit imposed on factory ammo in older chamberings, i.e. as in the 35,000 PSI limit on 8mmx57. I would like to be able to grab a box of factory rounds that will push 3000FPS or better at the muzzle and just go shooting. The 257 Bob was an early front runner, but even the +P load is SAAMI limited at 58K PSI vs 65K for the 6mm. That alone should tell you something about the respective performance of factory loads.

Speaking of which, I am 0 for 3 checking on local over the counter sources for 6mm Rem ammo. I know it can be ordered, and if I start shooting a lot I may very well handload yet, but it appears to be more scarce than I hoped. Cabelas is not far though, and I'm pretty sure they would have it.

Concerning barrels, twists, purpose, etc... I would certainly not be against using this rifle to take a deer if one wandered across my FOV in season. However, that is not my purpose as stated in the OP. I have other options for my primary hunting rifle. My plan is to use a varmint weight barrel and carve a sniper style stock and fit it with a bipod, so it will not be the lightest carry rifle. I was thinking of a 10:1 twist in a 26" barrel. Of the factory ammo offerings I would probably choose 80-85 grain bullets when I can find them. If I handload I would probably go with 75 gr.

This is faster than the 12:1 that gave Remington problems with the .244 in heavier bullet weights. While it may not be optimal for the very heaviest bullets, I figured in a longer barrel it ought to stabilize 100 gr bullets if that is all I can find.

What are your thoughts on this?