Free bore question and a bit of advise please.

POME
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Free bore question and a bit of advise please.

Postby POME » Mon Jul 13, 2015 9:37 pm

I have just finished reading Nathan Foster's reloading book and now a little confused about the seating depth for my 7-08. Nathan writes a little about free bore in calibers among others 7-08 and the need for the case neck to stabilize the bullet with extended travel before it reaches the rifling. Now my questions are if this is true then is a concentricty gauge a must to check the case necks after re sizing. If so what do people use. Also how much travel do people suggest as it could take a lot of experimentation to get it right.
I have not been able to get very good grouping with my 7-08 loads and i am now thinking this may be a possible reason.
Also I am now thinking that i could do with a OAL gauge as well to make sure i am getting this part of the job correct. What do people use themselves. Is the Hornady one worth getting. Are there others available?
Thanks in advance for any help.

Cheers Jon
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Rushy
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Re: Free bore question and a bit of advise please.

Postby Rushy » Tue Jul 14, 2015 6:10 am

I don't reload and am not a techno type at all Jon so can't help but here is what I would do to eliminate the human factor and the rifle from the equation. Go get some really consist.ent factory ammo such as the Federal Gold Medal and then get three or four other shooters to shoot a five round group with it. The results of this will show whether the shooter (you) is part of the problem and whether the rifle is part of the problem. If everyone shoots a crap grouping then it is likely the rifle, if some shoots a great group then you can't discount the shooter as part of the problem and if everyone shoots a great group then you are back to your original question and I can't help.
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POME
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Re: Free bore question and a bit of advise please.

Postby POME » Tue Jul 14, 2015 8:32 pm

Cheers Rushy
Had not thought that it could be me or the rifle. I can shoot 1/2" groups with my 22-250 so may give the factory ammo thing a try.
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veitnamcam
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Re: Free bore question and a bit of advise please.

Postby veitnamcam » Wed Jul 15, 2015 3:35 am

I built myself a concentricty gauge and batched my ammo by runout.
Groups shot with the worst runout were barely discern able from ammo with no runout.
It would be the last place I would be looking for a problem.
Is it one projectile you are having trouble with or everything?

Sent from my GT-I8160L using Tapatalk
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Scribe
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Re: Free bore question and a bit of advise please.

Postby Scribe » Wed Jul 15, 2015 10:25 am

It may be an old fashioned method but this worked for us and produced good accurate ammunition.

Put a projectile in a fired but not resized case so that the projectile protrudes well out past a factory load. Then chamber case and fully shut bolt and the projectile will contact the lands and be pushed back into the case.

Most rifle seem to like a small jump to the lands so seat projectile back a tiny measured amount from the lands. Set reloading gear now to deliver this length bullet.
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POME
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Re: Free bore question and a bit of advise please.

Postby POME » Wed Jul 15, 2015 9:07 pm

veitnamcam wrote:I built myself a concentricty gauge and batched my ammo by runout.
Groups shot with the worst runout were barely discern able from ammo with no runout.
It would be the last place I would be looking for a problem.
Is it one projectile you are having trouble with or everything?

Sent from my GT-I8160L using Tapatalk


So far have tried 140 g accubond, 140 g and 150 g Hornady ballistic tips. I have found 5 winchester silver tip factory ammo in the back of the safe so will give them a go as soon as i get a chance as i know that they shot well. If they dont then i may have to investigate the rifle. If they shoot well like they use to its back to the start.
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POME
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Re: Free bore question and a bit of advise please.

Postby POME » Wed Jul 15, 2015 9:35 pm

Scribe wrote:It may be an old fashioned method but this worked for us and produced good accurate ammunition.

Put a projectile in a fired but not resized case so that the projectile protrudes well out past a factory load. Then chamber case and fully shut bolt and the projectile will contact the lands and be pushed back into the case.

Most rifle seem to like a small jump to the lands so seat projectile back a tiny measured amount from the lands. Set reloading gear now to deliver this length bullet.

That is the method i do use and i think i am very close to the mark with it. But from there if i then seat the bullets i have tried so far 20 - 30 thou from the lands not only is the bullet not seated very far but the rounds won't load from the magazine because the are to long. At the moment they are seated 68 thou back just to get them to load from the magazine.
I am going to measure a factory round and then pull it and then do the OAL thing and see how much jump they give the bullet. Just as a comparison.
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Woody
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Re: Free bore question and a bit of advise please.

Postby Woody » Mon Aug 31, 2015 2:28 pm

Some rifles have a very long freebore. Some of mine are close to 200,000 thousands of an inch and there is no way you can get a round thet is loaded to only 20 thou from lands, to fit into the mag. These rifles are extremely accurate. You have not mentioned the type and size of bullet you are trying to load and this can have a major effect depending on bullet length and barrel twist rate and other factors. I suggest you contact Nathan with your problem and also consult the recommended COAL for your brass and for the bullet from those manufacturers loading data.
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