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Old May 29, 2013, 01:07 AM   #1
savagest
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Reloading .308 a few questions. COAL

Gun is a savage model 10. I just got all my primers and powders so I am beginning to mess around a bit before I get to actually reloading. One thing I have a question with is with COAL.

I have a unprimed shell and a 175 SMK bullet, I am trying to determine how long to seat my bullets by closing the bolt with a loose fitting bullet. The problem is that my Sierra reloading manual says COAL is 2.810" and the I am coming up with 2.83x in my rifle. I did this twice with the same results.

Will I be okay seating the bullet this far out?
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Old May 29, 2013, 01:46 AM   #2
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Yes you will be ok, make sure your brass is trimmed to length. I trimmed all my brass for my 308 to 51mm dead. Seating of bullets varies depending on your own rifle. There is no exact OAL to adhere to. If the brass is to long you could run into pressure problems.

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Old May 29, 2013, 04:58 AM   #3
higgite
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Just a heads up. If the 2.83x OAL puts the bullet into the lands, you may want to back off of that to avoid high pressure problems. The forum gurus (and I mean that complimentary) can explain the details better than I can. Hopefully, one will be along soon.
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Old May 29, 2013, 06:17 AM   #4
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As stated above, once you have found Your Max OAL with your choice of bullet , reduce that OAL by a few thousands (I reduce by .015) to start. Then begin your load development by starting with a low powder charge and working up.

Remember, this Max OAL you found is specific to your rifle and THAT particular bullet weight and design. Changing bullets will change your Max OAL.

BTW, the OAL listed in the manuals are only a reference letting the handloader know what was used during testing. It is in no way a requirement. Some manuals do not even list tested OAL it is that unimportant to the handloader.
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Old May 29, 2013, 12:40 PM   #5
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Thanks for the info. I was going to set the bullet off the lands. At 2.820 that gives me .012-014 jump.
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Old May 29, 2013, 06:00 PM   #6
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Don't forget that if you're using a magazine your rounds most probably won't fit and may need to be single loaded.
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Old May 29, 2013, 06:43 PM   #7
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Re: Reloading .308 a few questions. COAL

Quote:
Originally Posted by steve4102 View Post

BTW, the OAL listed in the manuals are only a reference letting the handloader know what was used during testing. It is in no way a requirement. Some manuals do not even list tested OAL it is that unimportant to the handloader.

It'd be good to note that the published OAL is generally seen as a minimum. What you tested for is the maximum.

Somewhere unbeteeen is usually the best.
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Old May 29, 2013, 07:00 PM   #8
savagest
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They fit into my magazine just fine. BTW.
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Old May 29, 2013, 07:39 PM   #9
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The Hornady manual suggest seating off the lands .020 I have loaded some rounds like that and it did improve my accuracy a little bit.
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Old May 29, 2013, 07:48 PM   #10
steve4102
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Quote:
It'd be good to note that the published OAL is generally seen as a minimum. What you tested for is the maximum.
Why would the published OAL be considered a Minimum?
One you think that it would be the Maximum as going longer usually increases pressure in a bottle necked rifle round.
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Old May 29, 2013, 08:10 PM   #11
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Re: Reloading .308 a few questions. COAL

My understanding is the shorter its seated reduces case capacity, while seating longer creates more empty space so pressure drops.
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Old May 29, 2013, 10:30 PM   #12
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The numbers for oal are MINIMUMS. Reason being, if u publish a maximum powder load, if you go shorter your pressure goes up and will exceed max. Your max is different on different guns. Mine personally is 2.87
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Old May 30, 2013, 05:20 AM   #13
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Quote:
My understanding is the shorter its seated reduces case capacity, while seating longer creates more empty space so pressure drops.
Quote:
if u publish a maximum powder load, if you go shorter your pressure goes up and will exceed max.

In straight walled pistol rounds, yes, in bottle necked rifle rounds, not so much. The shorter the OAL the farther the jump, the farther the jump the Less the pressure.

The longer the OAL the less the jump, the less the jump the higher the pressure.
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Old May 30, 2013, 02:16 PM   #14
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Re: Reloading .308 a few questions. COAL

Hmm interesting. I'd never read that before.
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Old May 30, 2013, 07:07 PM   #15
savagest
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Made my first few rounds today!! I made 7 successful.

Trimmed to 2.005
COAL 2.820
38.5 grains IMR 4064
SMK 175 HPBT

I will be working up from here.
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Old June 1, 2013, 04:57 PM   #16
steve4102
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Quote:
. Re: Reloading .308 a few questions. COAL
Hmm interesting. I'd never read that before.
UncleNick, a moderator here has chart graph that shows the relationship between OAL and. Pressure pretty well. Maybe he can post it up to view?
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Old June 1, 2013, 07:21 PM   #17
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At the range I shoot at most of the competitors that shoot 308
agree on 175 Sierra MK as their preferance

most use IMR 4064 or RE 15 with the 175's
most find that the Sierra MK 175 usualy shoots best at 10 to 15 off the lands

(All my rifles (5- 308s) prefer 4064 better than RE 15, and 10 to 15 off is where they like the
Sierra MK 175's)
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Old June 1, 2013, 07:30 PM   #18
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awesome info. I am going out tomorrow to shoot my loads that i built up. I have some starting at 38.5-42.3 jumping up in .5 grain increments, except the last one I only went .3. I did not want to go to max load yet.
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Old June 1, 2013, 10:29 PM   #19
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sweet spot for 4064 is around 42.0 gr and for RE 15 is about 43.0 gr
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Old June 3, 2013, 04:37 PM   #20
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Yep. Right at 43.3 grains RE15 and 175 SMK. 3.250" on the comparator, and @2.837 COAL. Lapua brass. Shoots really well without pressure signs in Spring and Fall. Will try again here in the Summer to see how it does.

Trying the same recipe in Lapua small primer brass, with various small rifle primers I had on hand, here next time I can get to the range... probably sometime in August. Figure to run these over the sky screens for a bit better grasp of data. Too bad I have to wait so long.
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Old June 4, 2013, 09:09 AM   #21
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Berger bullets has some pretty good ideas about load development. They are pushing their VLD bullets but the principle is the same. I do not shoot bullets loaded in the lands.

I load one into the lands to get the OAL. I then seat some following Berger guidelines and record the results. Once I find the "sweet" spot, I fine tune the seating depth. Once I find that, I fine tune the charge.

You will be AMAZED how the groups will diverge and then converge just by changing the seating depth.
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