Bullet Weight to Barrel twist

[brad925]

I am wondering what weight of bullet to use with my 1 in 20 twist barrel. I have a Uberti highwall in 45-70.

[Lead pot]

brad

It's not so much the weight as it is the length and profle of the bullet one should be conserned about, especially in a 1/20 ROT.

[Lead Fred]

405 gr RN, Lyman makes a real nice mold

[kokomokid]

The 457125 a short govt round nose at aprox 500gr shot great for me in a 20/1 twist. Also was easy to develop loads for.

[johnson1942]

kokomokid is right for a perfect bullet for you, however lead freds post will work also very well. i talked to shooter over in wyoming a few years back and he could hit the metal buffalo at 800 yards with what lead fred suggested and he stuck with that bullet.

[country gent]

Several barrel makers have charts up as to what twist/caliber combination will stabilize what length bullet. I cant remember where I seen them at though. I ussually but bullets by the hundred and test to find what the rifle likes before buying a mold. The initall bullets cost more but you only buy one mold ussually. 50-100 bullets can tell you alot about the performance. 1-20 twist I would try 380- short 500 grn bullets Maybe the lyman 457124? Its a 385 grn copy of the gov round nose.

[bigted]

another boolit not to be ignored for that 20 inch twist barrel ... the LEE 459-405-HB . this boolit sized and lubed thru my .460 inch Lyman size/lube press does very well in my 20 inch twist barrels. this boolit carry's enough lube in the huge grooves and the hollow base allows enough obturation to really grab the rifling. I have had good success with it and hardly any leading.

the LEE mold is cheap enough that to obtain one is pretty easy for most to obtain. I had this jewel for a couple years before I tried it and now wish I had been using it all this time. just wish it were a double cavity mold.

[Outpost75]

http://en.wikipedia.org/wiki/Miller_twist_rule

[montana_charlie]

Two or three of decades ago the 1 in 20 twist was the 'standard' for a singleshot rifle shooting a .45/70 family cartridge.
During that era the Lyman Postell (457132) was already popular for long range shooting.

I think it might be about the longest bullet suitable for that twist, but it can do well if you get it moving fast enough.

CM

[brad925]

Thanks for all the great info!

[brad925]

With the 459 405HB do I need to run a grease cookie with that boollit or can I?

[chill45100]

The Greenhill formula should help make a good choice. T equals 150/length. There is a calculator at www.kwk.us.twist.html

It worked for my 1-18 twist barrel.

[bigted]

With the 459 405HB do I need to run a grease cookie with that boollit or can I?

to use a cookie with this boolit will increase the amount of shots that can be accurately shot before a thorough cleaning to re-establish accuracy. your barrel will tell you what this number of shots are. also it depends on what type shooting you will use it for.

if hunting ... i have fired 20 of them with the resultant 2 to 2.5 inch accuracy at 100 yards which i consider way good enough for hunting.

if target shooting then to swab every shot is the best way to get the most accuracy and repeatability and if this is the drill then another boolit will serve better then the Lee. but the Lee will suffice for most things and the cookie is a good idea as well. just have to experiment with your particular rifle to see what it likes.

every rifle will mutter the needs if you will listen to it.

[Huvius]

I would try some experimentation with differing weights.
Anyone know if the Metford rifling in Gibbs Farquharsons is what enabled them to shoot both express bullets (360gr) and heavier bullets (500gr+) equally well?
Sure would be nice to have good loads for two vastly differing bullet weights.

[herbert buckland]

The express bullets used interchangabley were usually long bullets with a large holow point to reduce weaight,it is the lenth of the bullet that stabilises the bullet with a given twist rate + velocity has to be taken into acount,you have a bit to play with on booth acounts before acuracy sufers,the real trick is to get the the point of impact close with the diffrent bullets

[HNSB]

I was wondering the same thing a few weeks ago.
I stumbled on to the Greenhill calculator mentioned above, and it was very helpful.
The link in the post above is broken. It's: http://kwk.us/twist.html

[Boz330]

Here is another site run by one of the guys here. http://www.tmtpages.com/twistrate.htm


Bob