Reloading help/suggestions please chaps

[njc110381]

Right chaps. I've always thought myself to be a fairly competant reloader but I've come across something that's really got me beat! So I'm looking for some pointers!

 

My combi gun isn't grouping too well. Never really has and this has been confirmed by the fitting of the scope. I can't get inside 4" at 100 yards with the factory ammo I have and I think I've just sussed out why! I've always loaded about 20 thou from the lands, maybe more with Barnes TSX. Well as an experiment I thought I'd draw a pencil line around the bullet against the case and give it a few taps with the kinetic hammer to pull them out a bit, then stick them in the rifle and close it to get the approximate max OAL for that bullet type by seating them with the throat of the rifling. All seems simple you may say? What's the problem? Well...

 

Factory ammo is 2.855 OAL. I've hammered them out to 3.122 and pencilled a second ring on the bullet. They still close with no resistance. I tapped it a little more and out it fell, so less than a bullet width was inside the case at last known measurement! Arse! What should I do next?

[AndyCM]

Right chaps. I've always thought myself to be a fairly competant reloader but I've come across something that's really got me beat! So I'm looking for some pointers!

 

My combi gun isn't grouping too well. Never really has and this has been confirmed by the fitting of the scope. I can't get inside 4" at 100 yards with the factory ammo I have and I think I've just sussed out why! I've always loaded about 20 thou from the lands, maybe more with Barnes TSX. Well as an experiment I thought I'd draw a pencil line around the bullet against the case and give it a few taps with the kinetic hammer to pull them out a bit, then stick them in the rifle and close it to get the approximate max OAL for that bullet type by seating them with the throat of the rifling. All seems simple you may say? What's the problem? Well...

 

Factory ammo is 2.855 OAL. I've hammered them out to 3.122 and pencilled a second ring on the bullet. They still close with no resistance. I tapped it a little more and out it fell, so less than a bullet width was inside the case at last known measurement! Arse! What should I do next?

 

Are you reloading for this gun or staying with factory ?

I'd be inclined to check the twist rate and match bullet weight to that spec. Maybe the gun just doesn't like that bullet?

If there is a long throat and you have no prospect of seating 20 thou off you may need to go longer / heavier or just stick to SAMMI'ish.

 

What calibre is it ? ....... Ahhhhh 7x57R ?

- so 120g to 175g'ish bullet range - what are you using now ?

 

Cheers

AndyCM

[njc110381]

The pulled bullets are 140grn S&B. The bullet is .985" long and of round nose design. I'm thinking of getting some 175grn Hornady RN to try as they'd have to be a fair bit longer I'd say?

 

I've never had a bullet not reach the lands though? This is really baffling me! I'm thinking of pulling a few out to as long as I can sensibly get them to try. They're still a mile off though I recon!

[MarinePMI]

Crimp the rounds.

 

The single shot or combi rifles are notorious for exceedlingly excessive freebore (which is what this sounds like) to allieviate pressures and ease extraction (generally the weak point in a single shot rifle). You don't say what particular brand rifle, so I'm unsure if this is exactly the reason, though I know the Savage combo guns were known for it (Model 24 IIRC). Crimping will help allieviate the erratic pressure curves (caused by differing neck pull tensions and differing thickness in the brass' necks from factory ammo). Another area would be run out of the bullet. If the bullet is slightly off from the concentric center, the excessive freebore will amplify the slight deviations.

 

I'm not saying this will absolutely solve the problem, but it is probably a good place to start...

 

JMTCW...

[Andrew]

Another vote for a crimp. I am reasonably certain that will aid in accuracy for the reasons my good friend The Marine detailed.~Andrew

[njc110381]

I'll try a crimp. One thing that does bother me though is that perhaps I shouldn't just be adding a crimp to existing loads? Is it likely to increase the pressure by a noticeable amount?

[MarinePMI]

With the amount of freebore you're describing I'd not be too concerned over the crimp increasing pressures. In all likelihood, the crimp will just aid in getting uniform, stable pressure curves.

 

Just my thoughts...

[Ratwhiskers]

Quick freebore / C.O.A.L check.

 

Close the action.

Insert a cleaning rod from the muzzle.

Mark with tape at the crown where the rod enters the bore when it is fully inserted.

Open the action and slide out the rod.

Thinly tape a bullet to a pencil and insert it into the bore until it reaches a soft jam

Re insert the cleaning rod until it gently touches the tip of the bullet and again mark the rod at the crown with tape.

The distance between the two points on the tape will give you an indication of C. O. A. L. (complete overall length)

As the lads have said, in your situation a crip should improve on neck tension and pressures.

 

Also don't be afraid to try several types of bullet (or factory loads) before finding something the rifle actually likes.