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Old January 16, 2013, 09:07 PM   #1
acb
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308 seating depth

Just loaded a few 308 150gn fmj case length of 2.005 with 45gn bl-c(2) seated bullet to min oal of 2.800 but it is well short of cannalure . I was wondering if this is right shouldn't it be on the cannalure so I can crimp it not sure what to do any one got any idea about this .
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Old January 17, 2013, 06:25 AM   #2
Bart B.
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Leave 'em where they are. Bullets for .308's don't need to be crimped in. As long as they chamber easily, shoot the darned things.
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Old January 17, 2013, 07:34 AM   #3
wrightme43
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My understanding is that 2.800 is max overall length.
I seated my 150 gr to 2.770-2.775 which just puts the case mouth in the bottom 1/3 of the groove. It matches exactly with the remington 150 gr sp factory rounds my gun loves. I am in no way giving you advice. I am very very very new to this. I am only offering what I did as food for thought, and to make sure I am not screwing up. My cases were trimmed to 2.008 which was where my case trimmer stopped.
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Old January 17, 2013, 09:03 AM   #4
cw308
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2.800 OAL is used so the bullet will load from a magazine, are you targetshooting, what rifle are you using. I don't have a reloading book here so I can not check where your load is for BL-C 2. Lower OAL can be fine, some rifles like alittle free bore. My bolt 700 308 I seat 2.775, I tried 2.820 an it didn't shoot as well. I fire one round at a time, don't use the magazine, so OAL wouldn't matter if my rifle liked longer seated bullets. Remingtons have alot of fee bore in their barrels, OAL will chang from bullet & powder used, 2.775 is average oal for a 150 gr jhp. Be Safe Chris

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Old January 17, 2013, 09:25 AM   #5
Rimfire5
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The OAL you use and should use depends entirely on the chamber in your rifle. It also depends upon the ogive of the bullet - the spot where the bullet first will touch the rifling.

There is a great article in the new Berger reloading manual by Bryan Litz on page 148 that explains the subject and recommends that you adapt COAL of a load to your chamber for each bullet type (target bullets and hunting bullets are often very different).

Every bullet type has different dimensions and the ogive will be in a slightly different place (the shape of the bullet tip has a lot to do with it).
150 grain Sierra Match King bullets #2190 for example has a recommended OAL according to the Sierra Manual (5th edition) of 2.775.
However if your chamber is deep, you could easily seat your 150 SMK out to 2.810 and still not be close to the rifling.
Then again if your chamber is exactly to spec (pretty rare) you might find that at 2.810, the bullet is into the rifling and you can't close the bolt.

Sierra 150 grain soft Boat Tail bullets #2125 have a recommended COAL of 2.750. Both the #2125 and the #2190 are boat tail shapes but the #2125 has the ogive out further because the soft lead point requires a fatter tip.
At recommended COAL, both would have the ogive approximately the same distance from the rifling so the "jump" distance to reach the rifling would be the same.

From a practical standpoint, you won't know what your chamber depth is until you measure it. Most agree that you should leave 0.020 between the bullet ogive and the rifling if you don't want to increase the pressure.
BUT --- every bullet shape has a different ogive position so you really need to measure the chamber with each bullet type you use.

For example, I have a Savage 10 FP in .308 that has a deep chamber.
I can seat a 168 SMK out to 2.890 and be 0.020 off the rifling.
However, because the bullet shape is different, I can seat a Nosler Custom Competition 168 grain bullet out to 2.958 to get to 0.020 off the rifling.

My buddy's new Savage 10 FCP-K in .308 has a chamber that is much shorter and the 168 SMK bullet will be into the rifling if it is seated at 2.800 COAL. He has to load at 2.760 with the SMKs to get 0.020 to the rifling.

Both rifle shoot very accurately with their favorite loads and once we both knew the rifle's specs, we were each able to get the best out of our hand loads. We just had to load to totally diffenent COALs with each bullet type.
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Old January 17, 2013, 12:21 PM   #6
Ifishsum
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If you really want to crimp them, you need to seat to the cannelure. Otherwise, make sure they fit in the magazine and that they chamber easily and run them as they are. Are you loading for a semi-auto?
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Old January 17, 2013, 04:31 PM   #7
acb
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308depth

Thanks for info I am loading these for a semi-auto a Remington r25 . Bought a new manual today from hornady and they say seat them at 2.700 may have to switch to different powder though as hornady does not have recipe for bl-c(2) again thanks for replies .
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Old January 17, 2013, 07:05 PM   #8
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Cannelured bullets are designed for a specific caliber- and since there are a gazillion calibers that use .30 cal bullets, obviously those aren't designed for the .308...

Doesn't matter as said above.
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Old January 17, 2013, 08:15 PM   #9
Ifishsum
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Will seating them at 2.700 put you near the cannelure?

BL-C(2) is a fine powder for .308 - you don't need to ditch it just because it isn't in the Hornady book for that particular bullet. Other data for 150gr jacketed bullet is safe to use as long as you start 10% below max and work up. Metallic cartridge loading data isn't a strict "recipe" like shotshell data is, and OAL is not absolute. What fits the rifle is what is important.
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Old January 17, 2013, 10:01 PM   #10
acb
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Well I did go ahead and seat them on cannalure at 2.730 I did back load of a little to be safe. Loaded up twenty gonna shoot Saturday see how they work .
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