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257 Roberts Heavy Bullet 140gr Part II
travis3
Member Posts: 341 ✭✭✭
The reason I asked to start with, is I have a couple 100 6.5 cast bullets 140gr that measure .263. I was wondering why not size down to .259 or .260 and use them in a relatives .257 ackley Imp.
Comments
Glad to see you popped back in here.
Edit:
I dont' think we made it clear that it isn't weight that is the main factor in stabilizing bullets per a given rotation. Rather length. The longer the bullet the more rotation it requires.
In this specific instance, if you swaged those bullets down to .257 (entirely possible) you would probably also have to trim down the length to make them work in the .257 AI. While faster velocity does get you a tighter twist {edit: more rotation}, it won't be enough rotation to yet stabilize 140 gr. bullets. What you would need to do is trim the bullet length down to where each slug may weigh between 125-130. At that weight you will also need to have a shorter ogive, giving the bullet a shorter overall length.
About the longest bullet a 1-10" twist will stabilize is about 1.2" that is from anywhere in the 2600-3200 fps range. I doubt you can get lead going that fast. A 2000 fps load is more like what lead can do. If you had jacketed bullets it would be a different story.
I've made 1 shot kills on both moose and elk with standard .257 120gr bullets in my Ackley improved. I can't imagine why anyone would even try a 140gr bullet.
Because, with the right twist to stabilize them, they fly farther.
Not really. The velocity is limited by the caliber and .257 120 gr BT bullets have the best combination of velocity and sectional density you can get out of a 257 Ackley improved.
Not really. The best combination for long range shooting from a .257 cal with a 1-10" twist is the Berger 115 VLD.
As stated in the last post. With a 1-8" twist, the .257 Roberts can push a 140 gr. bullet to very competitive speeds. That I guarantee you, will fly a LOT farther than any 120 gr. bullets currently made for 1-10" twists. And remain accurate at extended ranges.
However, in this thread that point is moot. The OP wants to swage down 100 lead bullets to save $25-$30, and it's going to cost a lot more to do with maybe mixed results unless he goes for some big time bullet dies. Or knows someone who can do it.
Edit:
Travis3,
The point is it can be done. But, it's going to cost a bunch and still require your time. Unless you have a big supply of these that will make it worthwhile.
That said, if you trim the bullets down before you swage them you can use them. Here is RCBS's website with some equipment and prices to give you an idea what you may need:
www.rcbs.com
www.leeprecision.com
Go to bullet moulding and do some reading. RCBS had a .257 die which I believe is for swaging down bullets. If you have questions of them then use their contact info on their websites and give them a call. I always had someone helpful on the other end of the line.
-good luck