Seated "just touching" lands

[joelkdouglas]

Gents,

I ordered some Berger 115s to run through my 25-06. The Cartridge Base To Ogive (CBTO) measures from 2.668 to 2.670 inches. FWIW this equates to around 3.254 OAL to the lands. Measured with my Hornady comparator tool.

When adjusting OAL for accuracy (running a variation of OALs), I was going to start at the lands, 0.04 off, 0.08 off, and 0.12 off. However, this will be a potential hunting load, and I wouldn't want to remove a cartridge from the chamber and leave the bullet sticking in the barrel, emptying the powder in the chamber while hunting. Unlikely, I know.

Can I load 2.668 inches, or do I need to shorten just a smidge, to 2.667 or so? Any experience out there loading "to" the lands? I wouldn't expect it to be a problem, but I thought I might ask.

v/r
Joel

 

[DrMike]

Joel,

I've run my hunting loads as little as 0.005 inches off the lands without difficulty. Leaving a 0.010 inch jump is for sure enough.

 

[SJB358]

Same as Mike. Just .05" would be more than enough. It'll also allow plenty of space for a bullet that might be just a little outta spec.

 

[joelkdouglas]

Thanks gents. I'll go with the first set 0.005 off.

 

[Ridgerunner665]

I seat mine for .005" of the lands (30-06)....but most bullets will vary at least that much at the ogive.

.005" is just enough to ensure you don't unexpectedly go from kissing the lands to jammed into them.

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[woods]

IMO you guys are seating too close and risking pressure spikes

http://www.longrangehunting.com/forums/ ... fle-40204/

 

[Ridgerunner665]

I've read that, even discussed it with Berger...to sum it up...I was told if its working, don't change a thing.

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[ElmerThud]

I must have a hell of a long throat/freebore in my 25-06. Measuring the OAL from case head to bullet ogive with a comparator and bullet touching lands, the dimension in my rifle is 2.915".

My loads using the Nosler 110gn AB are seated and work superbly at 2.870" comparator. That's .045" off the lands and gives an overall cartridge overall length of approx. 3.390". I say approx. because although the ogive/head measurement is identical on each loaded round, the plastic tip seems to vary just a little, so the 'pointy' bit that doesn't matter at all, included in the OAL cartridge measurement affects the COAL measurement, but the ogive to lands dimension is constant at +/- .0005".
No matter how hard I try, I cannot get the variation tolerance closer.

But the upshot is - it doesn't make any difference. As long as my barrel has been fouled with 1 or 2 shots, the grouping is consistently tight enough to allow me to hunt succesfully.
Best wishes ET

 

[Guy Miner]

Joel - the whole idea of inadvertently pulling the bullet from the case and spilling all that powder into the action really isn't all that far fetched...

Was taking a fellow hunting a few years ago and he wanted to show me his very cool single shot rifle. He chambered a round, then went to extract it... Yes, he had loaded long, and the bullet stayed stuck in the rifling, dumping a case full of powder into the action when he opened it up. Ugh. It happens. Really worth thinking about when building hunting ammo. He had only used his rifle for target shooting to that point and had never ejected a loaded round.

Guy

 

[joelkdouglas]

I must have a hell of a long throat/freebore in my 25-06. Measuring the OAL from case head to bullet ogive with a comparator and bullet touching lands, the dimension in my rifle is 2.915".

My loads using the Nosler 110gn AB are seated and work superbly at 2.870" comparator. That's .045" off the lands and gives an overall cartridge overall length of approx. 3.390". I say approx. because although the ogive/head measurement is identical on each loaded round, the plastic tip seems to vary just a little, so the 'pointy' bit that doesn't matter at all, included in the OAL cartridge measurement affects the COAL measurement, but the ogive to lands dimension is constant at +/- .0005".
No matter how hard I try, I cannot get the variation tolerance closer.

But the upshot is - it doesn't make any difference. As long as my barrel has been fouled with 1 or 2 shots, the grouping is consistently tight enough to allow me to hunt succesfully.
Best wishes ET

Thanks ET. This rifle has a new barrel, and I bought the match reamer it's chambered with. That's the real reason for the short throat.

Don't worry--I'll shoot it out longer!

 

[joelkdouglas]

Joel - the whole idea of inadvertently pulling the bullet from the case and spilling all that powder into the action really isn't all that far fetched...

Was taking a fellow hunting a few years ago and he wanted to show me his very cool single shot rifle. He chambered a round, then went to extract it... Yes, he had loaded long, and the bullet stayed stuck in the rifling, dumping a case full of powder into the action when he opened it up. Ugh. It happens. Really worth thinking about when building hunting ammo. He had only used his rifle for target shooting to that point and had never ejected a loaded round.

Guy

Guy, what did he do? I would have been "mildly" worried I didn't get every bit of powder out of the action...I would worry the combustion would spread to the inside of the action, then my face!

 

[DrMike]

The bigger danger is that the powder will alter the chamber dimensions, creating pressure spikes. There isn't a great problem with ignition in the chamber. There is potential for a problem with chambering the next round.

 

[ElmerThud]

Thanks ET. This rifle has a new barrel, and I bought the match reamer it's chambered with. That's the real reason for the short throat. Don't worry--I'll shoot it out longer!

Ah, I understand more now why the difference. I think I'd probably like to have rather more clearance of ogive from the lands than .0005" - that's really close.

If I could make a load work giving some .005" off the lands, I'd prefer to be there for when in the field hunting and not just paper punching. I'd have an 'easier' mind to concentrate on the fieldcraft for the hunt and taking the shot. You just never know when that 'follow up' may be needed without issues to complicate matters.
Best wishes, ET

 

[Guy Miner]

Joel - the whole idea of inadvertently pulling the bullet from the case and spilling all that powder into the action really isn't all that far fetched...

Was taking a fellow hunting a few years ago and he wanted to show me his very cool single shot rifle. He chambered a round, then went to extract it... Yes, he had loaded long, and the bullet stayed stuck in the rifling, dumping a case full of powder into the action when he opened it up. Ugh. It happens. Really worth thinking about when building hunting ammo. He had only used his rifle for target shooting to that point and had never ejected a loaded round.

Guy

Guy, what did he do? I would have been "mildly" worried I didn't get every bit of powder out of the action...I would worry the combustion would spread to the inside of the action, then my face!

He hunted with a different rifle and cleaned the heck out of the single shot.