hey guys, for you guys that have a 260 and reload for it I wanted to know what your cartridge oal is when bullet is just touching the lands. I know it is different for every gun. I have a shilen 26 inch varmint contour barrel and i am using remington brass with 123 grain sierra matchkings. I am getting 2.860 just touching the lands. Does this sound about right to you guys. If so i am going to seat the bullet at 2.850 and go from there. thanks.
260 rem coal
- Thread starter rakatak
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trebark
Well-Known Member
My rounds are loaded to 2.85 with a 130grain JLK so they fit in an AI mag. This length is not even close to the lands on my rifle. My rifle was originally built as a single shot and throated for the 140berger. So my bullets are making a loooooooong jump. http://www.longrangehunting.com/forums/f53/my-260-mcr-59628/
Like you said though, all this is meaningless to your situation. Although a COAL of 2.86 on-the-lands sounds seems a little short, what you need to do is get yourself a Hornady OAL guage:
Hornady Lock-N-Load Overall Length Gage Bolt Action
With it, you will be able to determine almost exactly the OAL for that particular bullet when it touches the lands.
Then my recommendation would be to set back .010. So if you are 2.86 on-the-lands, you would load them to 2.76. .001 is not sufficient set back because you would have a hard time loading them that precisely. This would mean that some of your round would be on the lands and some off the lands. And that would cause you lots of fits.
Like you said though, all this is meaningless to your situation. Although a COAL of 2.86 on-the-lands sounds seems a little short, what you need to do is get yourself a Hornady OAL guage:
Hornady Lock-N-Load Overall Length Gage Bolt Action
With it, you will be able to determine almost exactly the OAL for that particular bullet when it touches the lands.
Then my recommendation would be to set back .010. So if you are 2.86 on-the-lands, you would load them to 2.76. .001 is not sufficient set back because you would have a hard time loading them that precisely. This would mean that some of your round would be on the lands and some off the lands. And that would cause you lots of fits.
Sully2
Well-Known Member
If they are 2.86 and you need to have loaded rounded mike at 2.76....you REDUCE by .10....not .010. 2.86-.010 gets you down to 2.85...
Sully2
Well-Known Member
I make my loaded rounds sit at .02 short of the rifling regardless of the bullet used. From 124 Lapua's to 15? grain ?? Barnes I think they are???
trebark
Well-Known Member
d'oh!
I made a dummy round by sizing a fired brass case then cut 2 slits down to the neck, then put a bullet in the case and put round in the gun and closed the bolt slowly. get right around the same measurement every time I do this. 2.858 to 2.860. Does this number sound right to you guys?
boomtube
Well-Known Member
"I wanted to know what your cartridge oal is when bullet is just touching the lands. I know it is different for every gun."
And, from that, you already know that what's "right" is different. Our's isn't your's and we don't have a clue what your chamber's dimensions are so anything you throw at us sounds right if it's right for you. ??
And, from that, you already know that what's "right" is different. Our's isn't your's and we don't have a clue what your chamber's dimensions are so anything you throw at us sounds right if it's right for you. ??
hey pal, i never asked for some sarcastic smart *** answer. I just wanted to know if all 260s ran in the same area as far as coal. I don't know i'm just getting into the reloading bit and was looking for a little guidance but as usual on all these forums there is someone who wants to act like you. To all you other guys that tried to help, I really appreciate it.
Sargesniper
Well-Known Member
Rakatak, All.260 chambers are not alike in reference to throat length even if they were chambered with the same reamer. There will be a slight difference but not enough to be concerned. The method you are using to measure COAL is fine for your chamber. From touching the lands to seating shorter is the way you will find the best seating depth for accuracy. Good luck and good shooting with your .260. ..... SEMPER FI!
Yaddio
Member
RAKATAK,
I agree with Sully2. My measurements for COAL on my Rem 700 using 142 MatchKing is 2.873, so you're in the ball park when compared to my rifle. When I measure COAL with a 120 Pro Hunter, the COAL is much lower due to the differences in bullet construction. BTW, the 142 matchking won't fit in my magazine, but this is OK since I load them one at a time for F-Class matches.
More important to me is CBTO, or Cartridge Base To Ogive. This measures the base of the cartridge to where the bullets contacts the rifling. I've enclosed a picture of my set up using a Stoney PT. gauge, now called the Hornady lock and load. Since you said you're new to reloading I suggest you buy one of these tools as part of your basic kit. You'll never regret it.
I too have measured like you did, (by splitting the case). I've done this by pinching the case mouth a little, then slowly chambering the cartridge. This gets you pretty close to the actual measurement, but some bullets will pull out slightly.
Interesting to me is that different type bullets measures slightly different CBTO. For example, my 120 Pro Hunter measure 2.290 CBTO and my 142 MK measures 2.285 CBTO.
I've loaded these 142 MKs 8 thousand off the lands.
Good luck and happy reloading.
I agree with Sully2. My measurements for COAL on my Rem 700 using 142 MatchKing is 2.873, so you're in the ball park when compared to my rifle. When I measure COAL with a 120 Pro Hunter, the COAL is much lower due to the differences in bullet construction. BTW, the 142 matchking won't fit in my magazine, but this is OK since I load them one at a time for F-Class matches.
More important to me is CBTO, or Cartridge Base To Ogive. This measures the base of the cartridge to where the bullets contacts the rifling. I've enclosed a picture of my set up using a Stoney PT. gauge, now called the Hornady lock and load. Since you said you're new to reloading I suggest you buy one of these tools as part of your basic kit. You'll never regret it.
I too have measured like you did, (by splitting the case). I've done this by pinching the case mouth a little, then slowly chambering the cartridge. This gets you pretty close to the actual measurement, but some bullets will pull out slightly.
Interesting to me is that different type bullets measures slightly different CBTO. For example, my 120 Pro Hunter measure 2.290 CBTO and my 142 MK measures 2.285 CBTO.
I've loaded these 142 MKs 8 thousand off the lands.
Good luck and happy reloading.
