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O-give length
#6012888
11/05/15 08:44 PM
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Joined: Jun 2009
Posts: 4,199
Korean Redneck
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This is probably another newbie question...
Is there such a thing as too short of an o-give length? I ask because factory ammo is about 0.020" longer than what I'm getting for my rifle. Is this any sort of a problem to seat it this short? Federal gm match 168 and 175 are about 2.225" and I think my lands about about 2.005-2.007".
More general question, if the factory ammo is longer than the chamber like I think mine is then does that mean I have just been jamming my bullet into the lands? Just curious.
I'm a dude who likes long barrels!
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Re: O-give length
[Re: Korean Redneck]
#6012895
11/05/15 08:46 PM
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Joined: Mar 2012
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Do you have a factory rifle? Or custom?
Most factory rifles have long chambers to accommodate all types of ammo.
If you bullet length is longer than chamber it will get pushed back when chambered. This can increase pressure due to compressed loads
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Re: O-give length
[Re: Korean Redneck]
#6012906
11/05/15 08:50 PM
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Joined: Dec 2008
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Man, if your ammo is 20 thousands longer than your chamber, that's a lot. Will the bolt close? Bolt gun? I doubt factory ammo is too long for your chamber. That too long stuff is usually relegated to hand loaders.
Cast I have a short attention spa
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Re: O-give length
[Re: Korean Redneck]
#6012908
11/05/15 08:51 PM
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Joined: Jun 2009
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Korean Redneck
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I have a factory savage with an aftermarket shilen barrel. My gunsmith told me held installed it "tight" because he knew what I was trying to do with this rifle.
And since I had the barrel installed, I feel like I've more tight closing rounds than I've experienced with my other bolt rifles, which are all totally factory.
Last edited by Korean Redneck; 11/05/15 08:53 PM.
I'm a dude who likes long barrels!
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Re: O-give length
[Re: Korean Redneck]
#6012933
11/05/15 09:05 PM
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Posts: 3,809
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Re: O-give length
[Re: Korean Redneck]
#6012942
11/05/15 09:12 PM
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Joined: Jun 2009
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Korean Redneck
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I'm a dude who likes long barrels!
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Re: O-give length
[Re: Korean Redneck]
#6012945
11/05/15 09:15 PM
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You have some once fired brass it sounds like. Mic it at the neck and compare that measurement to SAAMI spec. You might need to handload for that gun if it has a tight chamber.
Cast I have a short attention spa
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Re: O-give length
[Re: Korean Redneck]
#6012961
11/05/15 09:25 PM
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Joined: Jun 2009
Posts: 4,199
Korean Redneck
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Sorry, I should have been more clear. I am attempting to handload for the first time and was taking the sage advice of firemanjg on how to figure out the length of my lands and adjust the ogive seating depth to match. it took me a while to figure out how to do it correctly but I'm fairly certain of my measurement now. That's when I checked some factory ammo and discovered it was shorter.
So given that I have an aftermarket barrel, it is possible to have a scenario where it's shorter than factory by about 0.020"?
I'm a dude who likes long barrels!
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Re: O-give length
[Re: Korean Redneck]
#6012966
11/05/15 09:28 PM
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Hey, if you got JG on the job, you don't need my sage wisdom.
Cast I have a short attention spa
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Re: O-give length
[Re: Korean Redneck]
#6012970
11/05/15 09:30 PM
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Joined: Jun 2009
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Korean Redneck
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Haha, I'll take words of experience from anyone. That's actually why I love this forum. Great place just to bounce some ideas off of. Thanks for the feedback.
I'm a dude who likes long barrels!
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Re: O-give length
[Re: Korean Redneck]
#6012992
11/05/15 09:39 PM
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So I had some 175 smk loads and oal is 2.8. That chamber seems really tight
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Re: O-give length
[Re: Korean Redneck]
#6012997
11/05/15 09:42 PM
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Joined: Oct 2004
Posts: 39,544
redchevy
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Easy test can you put a factory round in it and close the bolt?
Does it leave marks on the bullet?
If not then you are measuring something wrong I would think.
It's hell eatin em live
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Re: O-give length
[Re: Korean Redneck]
#6013018
11/05/15 09:52 PM
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Joined: Jan 2009
Posts: 19,250
Judd
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Yes, that is controled by freebore on the reamer. It could make it hard for you to chamber a round because you're jamming that bullet .220...that is a LONG way to jam one. Once you close the bolt you definitely don't want to open it back up and pull it out because I would bet you will get an action full of powder and a bullet left in the bore. I've had this happen just jamming .020.
If it was me and based upon you telling us you are starting to reload...you can adjust your seater to seat those shells to the 2.005 that you have measured for that gun. Always easier to seat one deeper than it is to seat it longer.
So yes you have a small problem but it sounds like you have the tools to fix it.
Don't let your ears hear what your eyes didn't see, and don't let your mouth say what your heart doesn't feel
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Re: O-give length
[Re: Judd]
#6013028
11/05/15 09:56 PM
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Joined: Dec 2008
Posts: 41,173
J.G.
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Re: O-give length
[Re: Korean Redneck]
#6013047
11/05/15 10:03 PM
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Joined: Oct 2011
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IDoc
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Be careful of pressures, though. The more you stuff a bullet into the case, the more compressed the load is and the higher the pressures get with otherwise normal powder charges. I have a short throated 6mm that shows excessive pressures with loads a full 2gr under max book.
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Re: O-give length
[Re: redchevy]
#6013203
11/05/15 11:38 PM
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Joined: Dec 2009
Posts: 5,455
Big Fitz
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Easy test can you put a factory round in it and close the bolt?
Does it leave marks on the bullet?
If not then you are measuring something wrong I would think. Have you considered calling your gunsmith and asking him about this? It would seem to me trying redchevy's advice above is also warranted. I would expect rifling marks or some level of difficulty removing the round. Since you are reloading, try this with an unprimed and resized case with the bullet seated as planned. I am interested in hearing what you learn.
I was wrong...on anything technical. Fitz............. is right, ya know............
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Re: O-give length
[Re: Korean Redneck]
#6013779
11/06/15 03:49 AM
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Korean Redneck
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First of all, thanks for all the replies. I will definitely try when I can to see if a factory round leaves marks. Given what was said I'm going to try my first batch with the length I ended up measuring. And I will start will lower loads. I'm not sure if it matter but this a shilen reamed barrel. One of those direct replacement for savage model 12s.
Second, i am an idiot. It was 2.205" (not 2.005") versus 2.225" for the factory. It shorter but not as bad as I indicated on the op.
Last edited by Korean Redneck; 11/06/15 04:00 AM.
I'm a dude who likes long barrels!
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Re: O-give length
[Re: Korean Redneck]
#6013854
11/06/15 04:36 AM
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Joined: Feb 2012
Posts: 1,182
Dave3575
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different bullets are going to measure out differently. your not using the same bullet as whats in the factory ammo....
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Re: O-give length
[Re: Korean Redneck]
#6014033
11/06/15 12:37 PM
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Joined: Dec 2008
Posts: 41,173
J.G.
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One is twenty thousandths, the other is two hundred thousandths. The latter might as well be a mile, I had more faith in you than to make that much or a mistake But I'm glad those are the real numbers.
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Re: O-give length
[Re: Korean Redneck]
#6014041
11/06/15 12:42 PM
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Joined: Apr 2010
Posts: 6,219
dee
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Like most have mentioned it's a throat length that determines seating depth.
Coloring the bullet with a sharpie to look for land marks is what I do with a homemade case to check oal.
"A vote is like a rifle; it's usefulness depends on the character of the user" Theodore Roosevelt
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Re: O-give length
[Re: J.G.]
#6014127
11/06/15 01:41 PM
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Joined: Jun 2009
Posts: 4,199
Korean Redneck
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One is twenty thousandths, the other is two hundred thousandths. The latter might as well be a mile, I had more faith in you than to make that much or a mistake But I'm glad those are the real numbers. You would think as an engineer I'd check my numbers better. Just goes to prove God is merciful because I haven been fired or laid off yet! Haha So I assume .020" is not that big of a deal. As for the different bullet comment, I thought that was the reason for measuring the ogive to bottom of case dimension with a bullet comparator so it normalizes the measurement for any bullet regardless of manufacturer or type. I thought I can take this number and apply it to any bullet I reload. Am I wrong?
I'm a dude who likes long barrels!
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Re: O-give length
[Re: Korean Redneck]
#6014142
11/06/15 01:46 PM
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Joined: Oct 2004
Posts: 39,544
redchevy
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One is twenty thousandths, the other is two hundred thousandths. The latter might as well be a mile, I had more faith in you than to make that much or a mistake But I'm glad those are the real numbers. You would think as an engineer I'd check my numbers better. Just goes to prove God is merciful because I haven been fired or laid off yet! Haha So I assume .020" is not that big of a deal. As for the different bullet comment, I thought that was the reason for measuring the ogive to bottom of case dimension with a bullet comparator so it normalizes the measurement for any bullet regardless of manufacturer or type. I thought I can take this number and apply it to any bullet I reload. Am I wrong? You are correct. The distance to the lands will not change. Different bullet makes may/will have different over all lengths but the ogive should be the same if seated to the lands. Have you tried to chamber a factory round yet?
It's hell eatin em live
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Re: O-give length
[Re: redchevy]
#6014169
11/06/15 01:56 PM
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Joined: Dec 2008
Posts: 41,173
J.G.
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Exactly.
When I used 175 SMK then moved to 178 A-max case head to ogive length remained the same, OAL became linger with the A-max.
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Re: O-give length
[Re: Korean Redneck]
#6014305
11/06/15 02:56 PM
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Joined: Oct 2004
Posts: 39,544
redchevy
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Sorry to hijack, but how do yal say it...
O-give (pronounced "give" like I don't "give" a darn)
or
O-jive (pronounced "jive" like he was juking and "jiving")
It's hell eatin em live
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