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loading for a RRB #5 7x57....175 gr cast
the throat on this rifle is very long and if I set the seating depth of the boolit to where it is just shy of the lands the length of the boolit in the neck of the case is only about 1/2 the length of the case neck. Should I seat them deeper, say the full length of the case neck or is a depth 1/2 the length of the case neck sufficient?
thanks
atr
As you've described the condition, seating the bullet to half the depth of the case's neck should cause no problems.
DG
thanks DG
I will see how they perform
For range use they will be fine. Hield use where they are handled rougher it may become a little tricky as the bullets may get bumped around some.
thanks gent...understood
I've been trying to get a RRB in 7mm to shoot decent groups for a while. tried a NOE 175 grain sized to .290 Didn't shoot any better than the Lee 135 grain mold I lapped out to .289 or .290. Started off with tumble lubed lla. powder coating now. anything sized smaller than .288" didn't work very well
agcannon,,
the 175 gr that I shoot is pretty accurate, especially considering my old eyes and the iron sights of the #5 rolling block. At 75 to 100 yds I can pretty much hit a one gallon paint can consistently. No MOA accuracy but "serviceable". I have usually set the boolit to the crimp groove but thought I would try is further out to see if it makes any difference.
I was lucky, I guess, to grow up during the "Golden Age of Surplus." I recall the Remington Rolling Block invasion from all over the world, but mainly it seemed from Central and South America. Beautiful 7mm carbines in unissued condition for a price that even I could have squeezed out, but for some reason I always thought I needed a repeater. Age brings wisdom, they say.
After a few years I recall reading that many of the 7x57mm RBs had very bad headspace. That could be overcome by custom hand loading or re-barreling. I also read that the bores on many were oversized for jacketed bullets, but that they would perform quite well with cast loads.
Just a couple of years ago I read an article that claimed that the original dimensions of the 7x57mm cartridge were changed at some point, and that the RBs were correct for their time, but today the ammo is different. I can not say, and have never read another supporting reference. For sure, some may have received this or that alteration in the arsenals of their foreign owners, perhaps to accommodate domestic ammo production.
It certainly is a versatile rifle for making custom ammo, or for rebuilding into almost whatever suits your fancy. I've only got one, a .43 Spanish carbine. Lots of fun. I envy those with the original 7x57mm rifles as the 7mm is such a fine cartridge.
DG
Bird Hunter....
Yes, the golden age of surplus! When I was in hi-school I bought this #5 from a second hand shop on Hwy50 in California for $7.00. There was a barrel full of them!
I have not found head spacing to be an issue. I have shot both factory 175 gr J's and hand loaded 140 & 160 J's without a problem. The brass holds up well. The most fun to shoot has been the 175cast. The long throat and the tight twist in the rifling pretty much requires a heavy long boolit.
thanks for your thoughts
ATR
European [or original bore dimensions] for the military 6.5s called for a groove diameter of .266/.268 and for the 7x57 .286/.288. British dimensions for 6.5 and 7mm calibers called for .264 and .284. We, the US, went with the British standard. That is why commercial 6.5 and 7mm bullets are small for most 6.5 and 7mm made military rifles. Occasionally some commercial bullet makers will make jacketed bullets to fit either. I have some 160 gr Hornady 6.5s of .268 that are made for the milsurp cartridges. A lot of the older 7x57 milsurp bullets I have pulled ran .285 - .286. Thus milsurp barrels are not "oversized" as such but that most US made jacketed bullets are undersized for them.
interesting...thanks Larry
atr
atr,
I've got it shooting ok I guess, 1.25" or less at 25 yards. About as far as I can shoot in my backyard. I can't see too well anymore either.
It's the only gun I have with any sentimental value. My Dad bought it for $6.00 in the 1950's, and it hung on the wall in my parent's house for as long as I can remember. first centerfire rifle I fired when I was kid.
agcannon,
I have played a lot with my 7x57 and a couple of things seem to help with the accuracy.
seat the boolit in one operation
then
apply the crimp in a separate operation
when I apply crimp I do it by turning the die by hand,,,you can feel the crimp resistance. I find this more uniform than using the press/die to apply the crimp. My "technique" also helps account for varying case length.
One gallon cans at 50, 75 and 100 yds are my reference shooting ranges.
my loads are always 16 gr of 2400. The "classic" load
art
The 7mm Rolling Blocks had a ODD chamber.
I would take a 30-06 case and trim it to 57mm
Then start sizing the case in a 7x57 Mauser die until
such time at the block would lock up.
Then expand mouth with a Lyman M die
then continue to load the ammo as normal. (primer, powder, bullet)
This will give best minimal sizing and accuracy
Mike
I'm using a Redding bushing type neck sizer, with fire formed cases, then crimping with a Lee FCD, just enough to take the flare out of the case mouth.
I'm using 2400, too. seemed to do a little better around 17 -18 grains regardless of boolit weight
I have a carcano in 6.5x52 but the .264 bullets not big enough, my 7x57 probably needs more than .285 as well.
The 7x57mm is inherently accurate with the RCBS boolit.
https://i.imgur.com/LuRm5kSl.jpg