Bullet jump to rifleings

Catfish · #1 03-28-2010, 01:59 PM

I picked up a .17 MK 4 in Dec. and findly got it out to play with yesterday. After I worked my way up to 20.5 grs. of powder I started playing with bullet seating depth. I was loading 20 gr. Bergers, 20 gr. Hornadys, and 22 gr. Calhoons. When I started working up the powder load I had the bullets jammed hard into the lands, that way I don`t have to worry about presure goin up as I back them out. I found that this gun like the bullet to jump for best accuracy. The Calhoons shoot the best when jammed in with the first group fired being a .545. the H`s were .792 and the B`s were 1.425. Backed off .010 The C`s dropped to .250, the H`s to .712 and the B`s to .935. Another .020 deeper had the H`s down to .528, but got a .225 with the B`s. I pulled one of the C`s, and throughed it out to a .579 with 2 holes touching. I could not seat them any deeper as I had the seating die down against the rem and the seater screwed down as far as possible.

Seems this gun is more picky about bullet seating depth than any I`ve had in a while, but she sure does shoot when you giver her what she likes. The shooting was done with a 3 1/2 x 10 Leupold VX 3 so I`m sure I could do better if I were to put on a 24 or 30 X target scope.

Rapier · #2 05-21-2010, 01:08 PM

C-fish,
Some rifle just like the jump and do not care if it gets real long. When talking about such things, I like to use the 6.5x55 Swede as an example. The original 6.5x55 barrel is set up for a 156-160 gr bullet. With an 85gr Sierra they will shoot sub .5 inch groups all day. The bullet jump with the 85s has to be near the entire length of the 85s, yet they still shoot just fine.

Glad you got good results from yer 17.

Ed

Adam Helmer · #3 05-23-2010, 01:48 PM

Catfish,

Which reloading manual recommends you "jam the bullets hard into the lands?" Give your rifle what it likes, but I keep all my bullets a few thousands OFF the lands.

Adam

Adam Helmer · #4 05-24-2010, 12:41 PM

Catfish,

One more thing, IF you jam the bullets hard into the lands, you run the very real risk of a bore obstruction when you attempt to eject an unfired round-the bullet may STAY in the lands!

I recommend you stay a few thousands OFF the lands unless you want a stuck bullet.

Adam

357Maximum · #5 12-11-2010, 09:50 AM

Quote:

Originally Posted by Adam Helmer

Catfish,

One more thing, IF you jam the bullets hard into the lands, you run the very real risk of a bore obstruction when you attempt to eject an unfired round-the bullet may STAY in the lands!

I recommend you stay a few thousands OFF the lands unless you want a stuck bullet.

Adam

I also don't care for the sound of jamming anything that has to do with bullets or firearms for that matter. However: I have had exceptional shooting accuracy with very like neck tension, and seating the bullet to the lands. This method is only recommended for bench / target shooting where once you chamber the round you spend that round, otherwise you might experience a bullet being held by the lands and a load of powder being dumped into the action. (not fun) If during load development you are fortunate enough to have the sweet spot somewhere off the lands, mark that spot , make a dummy and consider yourself a happy old coot.

Catfish · #6 12-11-2010, 09:00 PM

You guy are correct about pulling bullets if you try to eject the round with out fireing it. And if your going to try that you jump presure so you need to start loading lower than recomanded starting load. And I have had to use the ramrod to tap out bullets that have pulled, but that`s all part of looking for the best accuracy you can ring out of a rifle.

Rapier · #7 12-12-2010, 10:40 AM

357,
In match shooting that all works great, unil one day you get an emergency cease fire with a clear all weapons order. Ask me how I know....

I had to walk off the line with an inoperable gun after the powder and spherical buffer dumped into the action. That was the end of the "Pope" practice with cast bullets for me.
Ed

357Maximum · #8 12-12-2010, 07:34 PM

Quote:

Originally Posted by Rapier

357,
In match shooting that all works great, unil one day you get an emergency cease fire with a clear all weapons order. Ask me how I know....

I had to walk off the line with an inoperable gun after the powder and spherical buffer dumped into the action. That was the end of the "Pope" practice with cast bullets for me.
Ed

Set the rifle on its butt, barrel up with a cleaning rod down the barrel with no jag and let it rest against the bullet. Open the bolt and hold, lightly push the rod and open the bolt about 1/4", hold bolt in place, remove rod, slowly open the bolt until you can grab and remove the cartridge.
It happens.

Rapier · #9 12-13-2010, 07:51 AM

I just started setting the bullet off by .003. Which had little effect on the accuracy and allowed me to set the bullets in an MTM box rather than have them laying on their side on a towel which is a PITB anyway. It all worked out and thankfully it was at a monthly local match and not a championship match.
Ed

mrmiskin · #10 12-14-2010, 11:49 AM

A quick question about seating just off the lands, dont you turn a rifle into a single shot when doing this since the ammo will be to long to fit in the mag?

Rapier · #11 12-15-2010, 07:31 AM

Good question,
If you are using a firearm of any kind with a magazine and intend on using that magazine to feed multiple rounds, the magazine length must be taken into consideration as well as the bolt face to lands length. However, the rolls reverse and the magazine becomes the absolute control. The nominal magazine OAL setup is the actual internal magazine length less .050 inches. I have at times gotten away with a bit less in a non critical set, but it is reccomended that an OAL be set with .050 clearance and for a critical set (DG hunting, defense, etc), that is what you want to do.

The Pope method of reloading and OAL setting is for single shot application and in the vast majority of shooting intended for and used with cast bullets. The cases are not resized, only deprimed and primed, a powder charge added with or without a buffer or wad, then the bullet set into the case mouth. The bullet is pulled out to extend the OAL past its final set, just before loading, which then allows the lands to set the exact OAL when the chamber is closed. You have absolute zero OAL clearance in the chamber and if the chamber is setup correctly you are centered X centered; with the bullet nose centered in the lands and the bullet base centered and supported by the case neck right up to the transition of the base leaving the neck. The result can be extreame accuracy with cast bullets. This method of reloading while accurate has some drawbacks mainly due to the loose bullet.
Best,
Ed

357Maximum · #12 12-15-2010, 08:45 PM

Quote:

Originally Posted by mrmiskin

A quick question about seating just off the lands, dont you turn a rifle into a single shot when doing this since the ammo will be to long to fit in the mag?

With light neck tension as I use on several cartridges, you should shoot just as if it's a single shot rifle. Several reasons. Here are a couple:
1.) Having a cartridge with light neck tension in a magazine is not advisable as the bullet making contact with any part of the breach, ramp, or action could push the bullet back in to the case.
2.) Recoil could cause the bullet to come loose in the magazine.

People that shoot this way are more like BR shooters in that one shot at a time rules the day.