Last weekend I puchased a sporterized 1936 mexican small ring mauser. It is chamberd for the 7X57. Its relly a prety neat little rifle.
I picked up the case adapter for the Hornady OAL gage, and the throat is alot longer than the magazine. A lot longer.
I put several bullets into the chamber to see witch one would come closest to the lands. and the sierra 160 HP BT was the closest at 0.109.
Now that is a lot of free bore.
I really like the way the barrel is coutoured. If its the origional military it was really done well.
But if it does'nt shoot, I have a small ring mauser to rebarrel.
I like the 7X57 prety well, but I could see rebarreling to 6mm REM or another Roberts.
I could do a .260 rem on it also a round I like.
But anybody think I am likly to get say 1.5 at 100 yards ?
If I had any round nose bullets on hand i would try them, thy tend to like free bore ...tj3006

I would treat this rifle just like any other.

I would pick a couple of bullets I like and start load development. I would seat the bullets to work through the magazine.

I would also probably buy a couple of boxes of different factory loads and shoot them to have a basis for comparison.


If it did not shoot as well as I liked, then I would seat the bullets farther out to see if accuracy really improved or to see if the bedding might need to be tweeked.

Keep us posted on your results.

+1

I'd buy some different bullets and find a load that works. For my 7x57's, the 140 grain bullet works best, with H-414 powder. But, lots of guys get good results with H-4350. Load the bullets as long as you can and still have them feed through the magazine and go for it. I gotta think that rifle will shoot. And, there are no flies on a 7 mm Mauser at all.

Don

try 154 gr Hornady Round noses..

The 154 is a good choice, but I think 175s might be better. The sights are probably regulated for that bullet weight/velocity combination anyway.

we seem to have similar ideas guys.
This rifle has no sights by the way.
It has a older bausch & loumb 1.5X6 20mm scope on it now.
I though at least sombody would say no way a rifle with that much free bore will shoot strait.
If the rifle shoots decently enough to stay with its currant barrel, I think I will put a barrel band front site on it and as for a rear, I think I will talk to negc abut the peep that goes onto weaver basses.
If it holds zero when removed I would have a leather guy build a little pouch for it and attach it to the sling. I would work up a load with a round nose. For the peep.
If I rebarrel to the Roberts, I might do the same.
That 117 grain Hornady RN has allways been lights out accurate for me, but I don't hunt with it beacuse there are lots of open spaces where I hunt and I like at leas a 300 yard load.
...tj3006

TJ I had a similar issue with a 6.5x55 sporterized that I picked up. I was shocked that I couldn't touch the lands with 120 or 140 grain bullets and have it seated to any depth that seamed like it would hold the bullet, it also had a dark bore so I really didn't have high hopes for it but it has turned out to be a real consistant 1" rifle and some loads are more than half that!
So don't fret about the freebore just shoot it!

Don't worry about is, being a ways from the lands may work fine. I've found a lot of .375's that the OAL was defined by the length of th e magazine, and I've never had a .375 that wouldn't shoot.

I tend to agree with you guys.
It may wel shoot just fine. And if it does great. I like the 7X57. if it does not , then I have a true short action mauser small ring action.
If I decided to rebarrel, I could do any thing from say a .358 X 284 to a .17 X.284.
But I am more likly to go with either the mauser case or the .308.
I have some silly notions about rounds fitting into actions based on history.
It would seem strange to build a 6.5X55 on a mexican action. Hell it would probably be a great rifle.
but a .260 would be just as good and somehow seems apropriate.
But some how I keep comming back to my favorite cartridge, the .257 roberts.
I just love the round. And this action is perfect for it.
A light sporter 22 inch tube, I could AI-it if I wanted.
My smith has a stock patern I really like and a good set of back up sights, regulated for the 117 grain Hornady round nose at about 2850 FPS, A 2 leaf rear site set at 100 and 150.
If it stays a 7X57 I will do the same with thehornady 154 grain RN.
...tj3006

In it's current configuration or rebarreled it's a sexy little rifle; I love Mexicans. I almost built one in .250 Ackley a year or two back. Not that there is anything wrong with having another rifle chambered for the Bob if that is what you barrel it to.