What a difference 0.5mm makes

[stug]

i have finally gotten around to reloading for my .404 Jeffery. My rifle came with some loaded rounds using Woodleigh 400gr RNSN. They were crimped at the top of the cannelure and measured 89.70mm base to tip of projectile.
I loaded mine to crimp at the top of the cannelure , but the measured closer to 89.80mm.
When I ran them through the magazine the second one down had jammed.
Going back through the data that came with the rifle the length should be 89.20mm. Reseating the projectiles to length now has them feeding flawlessly.
Only problem is it looks like the cannelure is too deep to be able to crimp.
Gives me an excuse to load a magazine full and see if the projectiles get pushed in on the last couple.

 

[PHOENIX PHIL]

I'd say you have two options.

1) Trim your brass enough to allow crimping into the cannelure at your 89.2mm COAL

2) Put a light crimp into the bullet even if it is outside of the cannelure. You don't have to crimp in the cannelure.

 

[stug]

Think I'll try your first idea of trimming to fit the cannelure.

 

[sestoppelman]

It is always preferable to crimp in the cannelure if you have one, but most times a crimp is not needed, if you have a tight grip on the bullet with the case neck. The .404 has a nice long neck so if its snug, it really shouldn't move. Given Phils choices I would trim the brass a tad, then crimp if its needed. I would not crimp on the bullet jacket.

 

[nztimb]

Stug, unless you have new brass, (I had trimmed all my brass for this very purpose) I was loading them with the canelure to the mouth of the case and they fed fine and in fact I did run a crimp the first few times I loaded them but felt that the need for the crimp just wasn't there so never did it again in the interest of brass longevity and numerous times ran magazines full of 400gn woodies at over 2300fps with never a concern for bullet movement in the case neck. I even left the bottom one in the mag for a couple of mag fulls and it was still ok.
I had my cast bullet mould made with the crimp groove cut to give it the same length as the woodleigh, from the front of the crimp groove to the front of the bullet and they were all loaded with the die set off a factory cartridge and everything was loaded to 89.2mm

 

[stug]

@Von Gruff I was using fired brass from the Woodleigh loads. I had loaded them a little too long initially. I was surprised how such a small difference stopped them jamming.

 

[JimP]

Does your reloading manual show the minimum and maximum for your cases and for the loaded round?

Also it sounds like the maximum over all length of the cartridge for the magazine has been altered in your rifle.

 

[stug]

My rifle is one that Von Gruff ( a member on here) made. It is made from an FN Mauser action. I am using his load data. His load data stated 89.2mm was the overall length. I seated the projectiles so I could crimp in the cannelure, as that looked like what the loaded loads that came with the rifle were.
When I ran them through the magazine they jammed, that's when I measured them and saw they were about 0.5mm too long.
I am pretty amazed that such a small amount would go from jamming to feeding flawlessly.

 

[nztimb]

It was in consultation with the GS that we made the mag that length so that there was the least ammount added to the front of the mag (least ramp and therefore lug abutment alteration) and to the rear to save shortening the bolt stop more than the minimum. Like most of the 404 capability the mag is just long enough with nothing surplus to requirments but certainly more than enough to get the job done in a fine fashion.