COL vs cannelure crimp

lakebilly · December 6, 2008, 05:56 PM

COL for 22-250 is 2.350. without cking some reloads i shot 11 casings that measured 2.414 diff of 0.064(no ill affect, thankfully) i reloaded new brass (Win) w/ Hornady 55gr.w/cannelure left minimall cannelure visible, length is 2.414. is this asking for trouble exceeding the "MAX"? does the cannelure have to be visible?

LB

amamnn · December 6, 2008, 06:04 PM

COL or COAL is not carved in stone. When you use a cannelured (IMHO a factory deformed) bullet, the case length will pretty much determine your COL
or COAL --another reason to avoid cannelured bullets, except for special (rare) applications.

**Shane Tuttle** · December 6, 2008, 06:29 PM

The below information is strictly my opinion on the subject and is not to be solely relied on as fact:

The cannelure is there for an availability to roll crimp. It's not necessary to perform a roll crimp, per se. I crimp just enough to rid of the mouth being belled for easy seating of the bullet. When neck sizing, the case will hold the bullet just fine.

For my own taste, I don't usually buy bullets with a cannelure for my .22-250. However, I did buy the same basic bullets as you did for fireforming my virgin cases. I never roll crimped them and didn't see any major accuracy issues nor signs of over pressure.

A key note: My gun is a bolt action. I think one of the main reasons for a cannelure on rifle cartridges is for semi-autos. The cartridges are more proned to be moved violently during the operation of a semi-auto. A roll crimp on the bullet assures that movement will not occur.

My OAL is 2.470" base to tip on Sierra MatchKings 52gr FMJ HPBT. However, I measure from the ogive, not the tip of the bullet. So this isn't the actual length I go by, but it gives you a comparison as to where you are with your lenght.

I found the sweet spot on my rifle by finding out how long the specific bullet can go until it touches the lands of the rifling. Then, I backed off about .020" and started low on my powder charges. REMEMBER, your rifle is going to be more than likely different from mine. Also, I'm practicing loads for accuracy, not for hunting.

If you deviate from 55gr. bullets, remember to check your rifle's twist rate and be sure to check for proper seating if you're going to continue to load longer than published OAL.

lakebilly · December 6, 2008, 06:42 PM

Sweet spot? proper seating? LB

**Shane Tuttle** · December 6, 2008, 07:18 PM

Quote:

Sweet spot?

The distance from the lands of the rifling to the contact point of the bullet. It usually contacts at the base of the ogive (curved portion of the bullet) and/or the beginning of the flat portion of the bullet. The optimal distance is a debatable subject between loaders. Some guns provide better accuracy when the bullet doesn't travel very far from the case to the rifling.

If the distance is far, relatively speaking, the bullet may have a chance to yaw a bit before hitting the lands. Once there, the bullet may leave the barrel in a yaw(crooked).

If the distance is close, you may not be able to have proper seating of your bullet. Also, if the bullet is touching the lands, excessive pressure could build up quickly. Again, this is debatable and I believe it all depends on the load recipe, cartridge, and type of rifle used. Be sure to do plenty of research on this subject if you plan to have the bullet "kissing" the lands for your pet loads. I personally like them close, but not touching the lands of the rifling.

Quote:

proper seating?

You want to make sure that the bullet is "pressed" down into the neck of the case sufficiently. If it's barely seated, i.e. only .015", you can have issues with the bullet not staying in place during cycling your round. Also, you can run into pressure issues with the cartridge with this scenario.

Basically, you end up playing with a large combination of items when reloading: Brands of components and types...

Cases, bullets, primers, powder, COAL. This is only the beginning. There's prepping the brass, also.

I hope I haven't confused or discouraged you. I put forth a lot of information and opinions. There's a lot to reloading. But if you start with the basics and take one step at a time, you'll be just fine.

Practice safety first and patience a close second. Ask plenty of questions from different people and do some reading. Hang in there.

lakebilly · December 7, 2008, 10:47 AM

Mr. T8
I appreciate anyone that would take the time to respond to what amounts to a call for help. I started collecting resources for reloading almost three yrs ago. Noone could discourage me when i make up my mind that i'm going to learn something. these forums, in my opinion have the best kinds of people america has to offer! i am going very slow, i am reloading for 9mm, .357, .45, .223, .22-250, .243 .30-06 so far. mostly for varmint. my kids like to shoot and i wouldn't do anything to make their exp. a nightmare. your advice, and everyone here is invaluable to say the least.
i don't expect this right to last much longer given the ignorance of the populace at large electing potential dictators.
"The biggest argument AGAINST a democracy is a five minute conversation with the average voter." W. Churchill

**Shane Tuttle** · December 7, 2008, 11:16 AM

If you think I'M helpful, wait until you get respones from others like CrustyFN, Shoney, wncchester, snuffy, T. O'Heir, etc.

They make me look like I should be playing with PlaySkool toys instead of operating a reloading press.

steve4102 · December 7, 2008, 01:05 PM

As stated above, COAL, OAL or COL is not written in stone. Here is what AA powders has to say about COL.

SPECIAL NOTE ON CARTRIDGE OVERALL LENGTH “COL”
It is important to note that the SAAMI “COL” values are for the firearms and ammunition manufacturers industry and must
be seen as a guideline only.
The individual reloader is free to adjust this dimension to suit their particular firearm-component-weapon combination.
This parameter is determined by various dimensions such as 1) magazine length (space), 2) freebore-lead dimensions of
the barrel, 3) ogive or profile of the projectile and 4) position of cannelure or crimp groove.

lakebilly · December 8, 2008, 05:31 PM

what's the best way to measure chamber, to the landings, and what is a safe distance if any for the bullet from the riflings? LB

Alleykat · December 8, 2008, 06:06 PM

Some folks use the RCBS Precision Mike. I use the Stoney Point tool with the dummy case. Sometimes I even use the comparator with the Stoney Point tool. Any distance off the lands is safe. I'm currently loading some rounds for my varmint AR .005" off the lands.

wncchester · December 8, 2008, 06:19 PM

OK Lake, after those kind words from Tuttle, who is no slouch himself, I'll add on to the good stuff you've already received about BOOK OAL vs. REAL OAL.

Let me abreviate "sweet spot", or accuracy "node", first. The terms refer to the (1) best powder charge range AND (2) the best seating depth range. Those ranges provide best accuracy and also allow a bit of variation both ways with little or no effect on accuracy. It's what good handloaders seek but don't always find!

Now, let me suggest you forget loading into the lands with a factory sporter if that's what you have in mind. Almost all of our rifles shoot best off the lands from .020" to as much as .100". Start developing your loads from 20 to 30 thou off the lands, find the charge node (or "sweet spot"). Then vary your seating depth, both ways, in maybe .005" increments until you find the seating node. It MAY be in the lands but not likely!

There is no "best" way to find the lands, several methods work. Perhaps the simplist is to make a seating dummy round to measure. First, lightly crimp/crush the neck of a fired case with pliers so it can pinch hold a bullet in place. Seat a bullet shallow and chamber the dummy, letting the lands drive the bullet back until the case is fully chambered. Withdraw it and use your calipers to measure OAL. As mentioned above, seat your starting rounds a bit deeper, knowing you will refine that length later.

No doubt about it, measureing OAL to the bullets ogive IS better than at the tips because the ogive curve of "identical" bullets do vary, and so do the tips of soft points, but what we really want is to gage the bullets jump to the rifleing when it's fired. A simple measurement to a tip may not - frequently won't - do that consistantly. BUT, if you haven't yet gotten the more sophsticated tools to do that just do it as described to get started. By the time it matters you will likely have a Hornady LnL OAL gage or the RCBS Precision Case Mic to do it more precisely.

And have fun!

wncchester · December 8, 2008, 06:26 PM

OK Lake, after those kind words from Tuttle, who is no slouch himself, I'll add on to the good stuff you've already received about BOOK OAL vs. REAL OAL.

Let me abreviate "sweet spot". The term refers to the (1) best powder charge range AND (2) the best seating depth range, the ranges that povide best accuracy and also allow a bit of variation that has little or no effect on accuracy. It's what handloaders seek but don't always find!

Now, forget loading into the lands with a factory sporter if that's what you have in mind. Almost all of our rifles shoot best off the lands from .020" to as much as .100". Start developing your loads from 20 to 30 thou off the lands, find the charge node (or "sweet spot"). Then vary your seating depth, both ways, in maybe .005" increments until you find the seating node. It MAY be in the lands but not likely!

There is no "best" way to find the lands, several methods work. Perhaps the simplist is to make a seating dummy round to measure. First, lightly crimp/crush the neck of a fired case with pliers so it can hold a bullet in place. Seat a bullet shallow and chamber the dummy, letting the lands drive the bullet back until the case is fully chambered. Withdraw it and use your calipers to measure OAL. As mentioned above, seat your starting rounds deeper, knowing you will refine that lenght later.

No doubt about it, measureing OAL to the bullets ogive IS better because the ogive curve of "identical" bullets do vary and so do the tips of soft points but what you really want is to gage the bullets jump to the rifleing when it's fired. A simple measurement to a tip may not - frequently won't - do that consistantly. And a good node can make such small variations irrelivant anyway. BUT, until you get more sophsticated tools, just do it as described to get started. By the time it matters you will likely have a Hornady LnL OAL gage or the RCBS Precision Case Mic to do it more precisely.

And have fun!

December 6, 2008, 05:56 PM	#1
lakebilly Member Join Date: May 6, 2008 Location: NY Posts: 41	COL vs cannelure crimp COL for 22-250 is 2.350. without cking some reloads i shot 11 casings that measured 2.414 diff of 0.064(no ill affect, thankfully) i reloaded new brass (Win) w/ Hornady 55gr.w/cannelure left minimall cannelure visible, length is 2.414. is this asking for trouble exceeding the "MAX"? does the cannelure have to be visible?LB __________________ "Our destruction... From the innattention of the people to the concerns of their government... fail properly to scrutinze their conduct; that in this way they may be made dupes of designing men..." D. Webster

December 6, 2008, 06:04 PM	#2
amamnn Senior Member Join Date: May 13, 2006 Location: WA, the left armpit of the USA Posts: 1,323	COL or COAL is not carved in stone. When you use a cannelured (IMHO a factory deformed) bullet, the case length will pretty much determine your COL or COAL --another reason to avoid cannelured bullets, except for special (rare) applications. __________________ "If the enemy is in range, so are you." - Infantry Journal

December 6, 2008, 06:29 PM	#3
Shane Tuttle Staff Join Date: November 28, 2005 Location: Montana Posts: 9,443	The below information is strictly my opinion on the subject and is not to be solely relied on as fact: The cannelure is there for an availability to roll crimp. It's not necessary to perform a roll crimp, per se. I crimp just enough to rid of the mouth being belled for easy seating of the bullet. When neck sizing, the case will hold the bullet just fine. For my own taste, I don't usually buy bullets with a cannelure for my .22-250. However, I did buy the same basic bullets as you did for fireforming my virgin cases. I never roll crimped them and didn't see any major accuracy issues nor signs of over pressure. A key note: My gun is a bolt action. I think one of the main reasons for a cannelure on rifle cartridges is for semi-autos. The cartridges are more proned to be moved violently during the operation of a semi-auto. A roll crimp on the bullet assures that movement will not occur. My OAL is 2.470" base to tip on Sierra MatchKings 52gr FMJ HPBT. However, I measure from the ogive, not the tip of the bullet. So this isn't the actual length I go by, but it gives you a comparison as to where you are with your lenght. I found the sweet spot on my rifle by finding out how long the specific bullet can go until it touches the lands of the rifling. Then, I backed off about .020" and started low on my powder charges. REMEMBER, your rifle is going to be more than likely different from mine. Also, I'm practicing loads for accuracy, not for hunting. If you deviate from 55gr. bullets, remember to check your rifle's twist rate and be sure to check for proper seating if you're going to continue to load longer than published OAL. __________________ If it were up to me, the word "got" would be deleted from the English language. Posting and YOU: http://www.albinoblacksheep.com/flash/posting

December 6, 2008, 06:42 PM	#4
lakebilly Member Join Date: May 6, 2008 Location: NY Posts: 41	Rem 700 VSSF bolt action 1:14 twist Sweet spot? proper seating? LB __________________ "Our destruction... From the innattention of the people to the concerns of their government... fail properly to scrutinze their conduct; that in this way they may be made dupes of designing men..." D. Webster

December 7, 2008, 10:47 AM	#6
lakebilly Member Join Date: May 6, 2008 Location: NY Posts: 41	Thanks Mr. T8 I appreciate anyone that would take the time to respond to what amounts to a call for help. I started collecting resources for reloading almost three yrs ago. Noone could discourage me when i make up my mind that i'm going to learn something. these forums, in my opinion have the best kinds of people america has to offer! i am going very slow, i am reloading for 9mm, .357, .45, .223, .22-250, .243 .30-06 so far. mostly for varmint. my kids like to shoot and i wouldn't do anything to make their exp. a nightmare. your advice, and everyone here is invaluable to say the least. i don't expect this right to last much longer given the ignorance of the populace at large electing potential dictators. *"The biggest argument AGAINST* a democracy is a five minute conversation with the average voter." W. Churchill** __________________ "Our destruction... From the innattention of the people to the concerns of their government... fail properly to scrutinze their conduct; that in this way they may be made dupes of designing men..." D. Webster

December 7, 2008, 11:16 AM	#7
Shane Tuttle Staff Join Date: November 28, 2005 Location: Montana Posts: 9,443	If you think I'M helpful, wait until you get respones from others like CrustyFN, Shoney, wncchester, snuffy, T. O'Heir, etc. They make me look like I should be playing with PlaySkool toys instead of operating a reloading press. __________________ If it were up to me, the word "got" would be deleted from the English language. Posting and YOU: http://www.albinoblacksheep.com/flash/posting

December 7, 2008, 01:05 PM	#8
steve4102 Senior Member Join Date: December 23, 2005 Location: Minnesota Posts: 2,952	As stated above, COAL, OAL or COL is not written in stone. Here is what AA powders has to say about COL. SPECIAL NOTE ON CARTRIDGE OVERALL LENGTH “COL” It is important to note that the SAAMI “COL” values are for the firearms and ammunition manufacturers industry and must be seen as a guideline only. The individual reloader is free to adjust this dimension to suit their particular firearm-component-weapon combination. This parameter is determined by various dimensions such as 1) magazine length (space), 2) freebore-lead dimensions of the barrel, 3) ogive or profile of the projectile and 4) position of cannelure or crimp groove.

December 8, 2008, 05:31 PM	#9
lakebilly Member Join Date: May 6, 2008 Location: NY Posts: 41	length of chamber? what's the best way to measure chamber, to the landings, and what is a safe distance if any for the bullet from the riflings? LB __________________ "Our destruction... From the innattention of the people to the concerns of their government... fail properly to scrutinze their conduct; that in this way they may be made dupes of designing men..." D. Webster

December 8, 2008, 06:06 PM	#10
Alleykat Junior member Join Date: July 26, 2007 Posts: 3,668	Some folks use the RCBS Precision Mike. I use the Stoney Point tool with the dummy case. Sometimes I even use the comparator with the Stoney Point tool. Any distance off the lands is safe. I'm currently loading some rounds for my varmint AR .005" off the lands.

December 8, 2008, 06:19 PM	#11
wncchester Senior Member Join Date: December 1, 2002 Posts: 2,832	OK Lake, after those kind words from Tuttle, who is no slouch himself, I'll add on to the good stuff you've already received about BOOK OAL vs. REAL OAL. Let me abreviate "sweet spot", or accuracy "node", first. The terms refer to the (1) best powder charge range AND (2) the best seating depth range. Those ranges provide best accuracy and also allow a bit of variation both ways with little or no effect on accuracy. It's what good handloaders seek but don't always find! Now, let me suggest you forget loading into the lands with a factory sporter if that's what you have in mind. Almost all of our rifles shoot best off the lands from .020" to as much as .100". Start developing your loads from 20 to 30 thou off the lands, find the charge node (or "sweet spot"). Then vary your seating depth, both ways, in maybe .005" increments until you find the seating node. It MAY be in the lands but not likely! There is no "best" way to find the lands, several methods work. Perhaps the simplist is to make a seating dummy round to measure. First, lightly crimp/crush the neck of a fired case with pliers so it can pinch hold a bullet in place. Seat a bullet shallow and chamber the dummy, letting the lands drive the bullet back until the case is fully chambered. Withdraw it and use your calipers to measure OAL. As mentioned above, seat your starting rounds a bit deeper, knowing you will refine that length later. No doubt about it, measureing OAL to the bullets ogive IS better than at the tips because the ogive curve of "identical" bullets do vary, and so do the tips of soft points, but what we really want is to gage the bullets jump to the rifleing when it's fired. A simple measurement to a tip may not - frequently won't - do that consistantly. BUT, if you haven't yet gotten the more sophsticated tools to do that just do it as described to get started. By the time it matters you will likely have a Hornady LnL OAL gage or the RCBS Precision Case Mic to do it more precisely. And have fun!

December 8, 2008, 06:26 PM	#12
wncchester Senior Member Join Date: December 1, 2002 Posts: 2,832	OK Lake, after those kind words from Tuttle, who is no slouch himself, I'll add on to the good stuff you've already received about BOOK OAL vs. REAL OAL. Let me abreviate "sweet spot". The term refers to the (1) best powder charge range AND (2) the best seating depth range, the ranges that povide best accuracy and also allow a bit of variation that has little or no effect on accuracy. It's what handloaders seek but don't always find! Now, forget loading into the lands with a factory sporter if that's what you have in mind. Almost all of our rifles shoot best off the lands from .020" to as much as .100". Start developing your loads from 20 to 30 thou off the lands, find the charge node (or "sweet spot"). Then vary your seating depth, both ways, in maybe .005" increments until you find the seating node. It MAY be in the lands but not likely! There is no "best" way to find the lands, several methods work. Perhaps the simplist is to make a seating dummy round to measure. First, lightly crimp/crush the neck of a fired case with pliers so it can hold a bullet in place. Seat a bullet shallow and chamber the dummy, letting the lands drive the bullet back until the case is fully chambered. Withdraw it and use your calipers to measure OAL. As mentioned above, seat your starting rounds deeper, knowing you will refine that lenght later. No doubt about it, measureing OAL to the bullets ogive IS better because the ogive curve of "identical" bullets do vary and so do the tips of soft points but what you really want is to gage the bullets jump to the rifleing when it's fired. A simple measurement to a tip may not - frequently won't - do that consistantly. And a good node can make such small variations irrelivant anyway. BUT, until you get more sophsticated tools, just do it as described to get started. By the time it matters you will likely have a Hornady LnL OAL gage or the RCBS Precision Case Mic to do it more precisely. And have fun!