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Old September 14, 2018, 04:36 AM   #1
Join Date: April 22, 2016
Location: New Mexico
Posts: 46
Throat wear

Hello all. I came up with a question reading off the "Barrel shot out, half shot out" thread.
One of the replies that came up has to do with seating the bullet out to or close to the lands. I have a few "used" rifles that I cannot seat the bullet up to the lands and have at least a caliber of seating depth in the case. Does this mean my throat(s) are worn/shot out to a point? If if does, would the fix be to set the barrel back and ream it to the proper point where I can touch the lands and have at least a caliber of seating depth for proper neck tension?
Also, what are your opinions on how much seating depth do I need for proper neck tension for hunting use? I have always used a caliber of depth as a rule of thumb.
Thanks for your opinions.
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Old September 14, 2018, 06:29 AM   #2
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It's not just the depth of seating ,it's the gripping force of the case. When holding the cartridge in your hand , gripping with the fingers , thumb on the bullet , if you can move the bullet without too much force the grip is not enough. Sometimes eliminating the expander is enough or get a proper expander diameter.
Always remember to do what your gun wants which is not always what you want . One caliber should do it . Nothing is gained by the bullet going beyond the curve ,
And Watson , bring your revolver !
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Old September 14, 2018, 07:11 PM   #3
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It depends on firearm type(bolt, lever, semi-auto, break open) .
It also depends on the cartridge.

Throats for say a 284 Win can be rather long.
Ditto some old military rifles due to the original use of a long heavy round nosed bullet.
Weatherby Magnums are known to have a long freebore.

I believe i'm the one your refering to. My case was a 7mm-08AI shooting a 140gr Berger VLD Hunting seated 0.005" off the lands.

Let us know what cartridge and make/model of rifle.
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Old September 14, 2018, 09:13 PM   #4
Join Date: April 22, 2016
Location: New Mexico
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I have (2) 25-06’s. One is an Interarms, the other is a Marlin MR7. Interarms Mark X in a 30-06 and a Weatherby vanguard in .308. None of these can get close to the lands with more than .120” seating depth.
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Old September 15, 2018, 05:54 AM   #5
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If they shoot good don't worry about it. A lot depends on bullet weight and type of ogive. A new 300 win mag case doesn't have neck length of .308.
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Old September 15, 2018, 12:27 PM   #6
T. O'Heir
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"...touch the lands..." It's not "touch the lands". It's "off the lands". How far 'off the lands' is a 100% trial and error thing too. Every chamber is different and there is no formula to determine how far off the lands that particular chamber prefers.
And that whole thing is just a load tweaking technique that isn't done until you've worked up the load. Just use the MAX OAL given in your manual and fiddle with the OAL 'off the lands' stuff after you have a load. If you feel like it. The 'off the lands' stuff rarely makes any difference in a hunting rifle.
Like sako2 says, if they shoot well enough, that being consistent minute of deer accuracy, leave alone and don't worry about it.
Long, heavy, round nosed, bullets haven't been used by any military for well over 100 years.
Spelling and grammar count!
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Old September 15, 2018, 12:55 PM   #7
SGW Gunsmith
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Join Date: December 31, 2014
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Several years ago I made the purchase of a "bore scope". Mainly, this purchase was due to customers telling me that their barrel was shot out and they felt that they needed a "re-barrel job".
Aftermarket barrels have gotten to be quite pricey, especially the premium brands. Then, threading, crowning and chambering come into play, and, bluing, if it's a chrome moly barrel.

I'm not one of those who always says, sure, OK, I'll get that done for you. I'll take the time to inspect the bore to actually see if the customers prognosis has any merit..........or not. No other way to do that without a bore scope. Many times I have found a carbon ring or bullet jacket material at the point where the throat transitions into the lands and grooves of the bore. Once removed, the rifle shoots once again back to where the customer previously experienced. For me, there's no other was to actually find out what's going on in the bore unless I can see what the bore looks like. If I find that the throat, leade and beginning of the lands/groove have carbon, or copper build-up, I'll remove any of that build up and then ask the customer for some of his favorite ammunition for that rifle, or I'll get factory stuff. I used to see some notorious copper fouling with Barnes X bullets until they started coating those bullets. The Barnes X bullets are solid copper and need to be made longer, because copper is much lighter than lead, to get the bullet weight to where reloading folks want it to be. A longer bullet creates a longer bearing surface that provides much more contact area engaging the lands and grooves. Once I get all fouling removed, another bore inspection is done to see if the removal of the fouling has exposed any internal rifling faults.

.22 rimfire bores are a whole world unto themselves, and a group of firearms that I really enjoy working with. But they do have circumstances involving the chambering and internal bore finish that makes those guns unique.
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