COL question

[Greenjoytj]

Is it more important to seat bullets to the load recipes cartridge overall length (COL), or to get the bullet inserted to be close to the forward edge of the cannelure?

I'm new to reloading so looking in my Lee #2 manual it says to have the case mouth near the forward edge of the cannelure for crimping. To get to the recipe COL I have to seat the bullet further out with the case mouth closer to the rear edge of the cannelure. I suspect seating the bullet to the recipe's COL is more important in order to keep pressure inline with the manuals published test pressure.

I am loading for the first handgun I've ever owned, it a new S&W 686 "Competitor" model 357 Magnum 6" barrel 6 shot cyl.

 

[ken158]

Just crimp in the cannelure and you will be fine.

 

[bigggbbruce]

I like to seat so that I can see a just little cannelure so the crimp is fully rolled to the minimum.

 

[iPac]

I am sure I don't do it properly, but I seat the bullet to the forward 1/4 of the bullets cannelure. This is for all of my 38spl, 357mag, and 44mag rounds that require the roll crimp.

The round rarely comes out the exact COL, but I have never had an issue. I don't load anything over max specs for the powders I use, so I guess that poses less risk. I have never felt differences in pressure or power between any of my rounds and they all shoot fine.

I understand that the amount of 'free air' you have in the case is what determines the pressure I guess. However, when it comes to the loads I do, the negligible difference between COL and what they actually end up being doesn't affect much of anything.

I don't load extensively for all calibers. Just handgun loads, and only use 2 different powders. Maybe I am lucky, or my powders are more forgiving. But I see no difference being a little off.

When I do 9mm with a taper crimp, then I seat to COL.

 

[Rpg]

I don't worry so much about OAL as I do about what works.

I set my reloading gear so that the result works every time in all my 1911's.

That's just me. May not be a best practice
M

 

[Nemo288]

For full pressure magnum loads you should observe the COAL (or make it longer).
For the rest; revolver rounds should actually be crimped in the middle or towards the rear of the cannelure.
You are trying to prevent the bullet going forward under recoil.
Ditto double rifle ammo.
For lever gun rounds I crimp near the front of the cannelure as you are trying to prevent the bullet being pushed into the case.
Just remember shorter = higher pressure.
Longer = lower pressure.
This effect can be dramatic, changing pressure by 5-10Kpsi with a .1" change.

Given all that, in reality I usually just settle for the middle of the cannelure.
A good crimp and neck tension, the bullet is not moving.

 

[BLUEDOT37]

To get to the recipe COL I have to seat the bullet further out with the case mouth closer to the rear edge of the cannelure.

In revolvers if you're using the exact same bullet in the reloading data don't sweat the COAL" being off a smidge, just crimp it in the cannelure. Small manufacturing differences in the nose contour affect that reading, when seating, as does deforming of soft noses during seating.

Work up the load if high pressure is a concern.

If it's a difference bullet, it can be another story, just depends.

.

 

[rwsmith]

It depends on the cartridge......

Cartridges based on those held over from black powder days such as the .38, .357, .44 Special, .44 magnum and .45 Colt are relatively insensitive to COAL and you can put the bullet at the cannelure or anywhere it 'looks' right along the shank for whatever purpose you are loading for.

More modern high pressure cartridges such as the 9mm, .40 S&W, 10mm, etc. are much more sensitive to COAL and should be loaded to the recommended lengths with a few thousandths of an inch in either direction 'wiggle room'. If you are near or at max loads, load exactly as the data recommends or longer. Never shorter.

 

[Pisgah]

The overall length is not a specification for the cartridge; it's a description of the round as loaded. Meaning you'll only get that COL in your loads if you use exactly the same bullet and exactly the same brass trimmed to exactly the same length as the brass they used, and crimped in exactly the same spot on the cannelure as they used.

Of course, this is rarely if ever the case, but they're just letting you know that "with EXACTLY this load, these are the results we got", and not "you must load exactly to this recipe". To the contrary, the standard instruction is "here's what we got, but you should start with a lower charge and work up to see what you get-- just don't go further than this load."

 

[ageingstudent]

Is it more important to seat bullets to the load recipes cartridge overall length (COL), or to get the bullet inserted to be close to the forward edge of the cannelure?

I'm new to reloading so looking in my Lee #2 manual it says to have the case mouth near the forward edge of the cannelure for crimping. To get to the recipe COL I have to seat the bullet further out with the case mouth closer to the rear edge of the cannelure. I suspect seating the bullet to the recipe's COL is more important in order to keep pressure inline with the manuals published test pressure.

I am loading for the first handgun I've ever owned, it a new S&W 686 "Competitor" model 357 Magnum 6" barrel 6 shot cyl.

With .38 the cartridge has a lot of room inside the case to move that COAL around. It's a very forgiving cartridge in that respect and a good one to start on. If your bullet has a cannelure and is a close cousin of the bullet in the manual crimp it in the cannelure. If you look at some factory rounds some of them crimp mid cannelure, some to the rear, some to the fore, and some no crimp at all. So much for consistency.

Note that The Lee manual does not give very specific information for projectiles, except for XTP and a few other projectiles. There's a mind boggling number of bullet shapes and lengths just in the 158 gr category. If you can't find data for the specific bullet you are using, look for something very similar and go with the OAL for that projectile. It's highly unlikely you will mess up a 686 with a .38 cartridge Unless you're being wildly irresponsible, but if you set your cartridge up as close to the data the manuals give as possible, in general you'll get decent results and can tweak the load for your gun from a solid starting point.

The Lee manual is a great place to look for ideas, it has a lot of compiled data from lots of different sources, but for specifics look to other manuals or reputable online sources that have more info on specific projectiles.

 

[twodog max]

Opinions and preferences are all over the board on this subject. No wonder newcomers are confused. There is so much variability in brass, bullets, tolerances in bullets and on and on that to worry about a few thousands of an inch difference on COL seems a little to much to me. I crimp everything that requires a crimp where the cannelure is just barely visible. I cannot remember why long ago I started doing this but I have done so for a long time. I do this with revolver ammo including magnums and rifle ammo like 30/30 and 45/70. The only ammo that ever jumped crimp was in a 348 Winchester and that was because the expander button was a little generous and a smaller button solved that problem. If you don't make a practice of operating on the top end ragged edge of pressures you will not need to worry to much about minute differences. From a safety standpoint anyway.

 

[mikld]

The overall length is not a specification for the cartridge; it's a description of the round as loaded. Meaning you'll only get that COL in your loads if you use exactly the same bullet and exactly the same brass trimmed to exactly the same length as the brass they used, and crimped in exactly the same spot on the cannelure as they used.

Of course, this is rarely if ever the case, but they're just letting you know that "with EXACTLY this load, these are the results we got", and not "you must load exactly to this recipe". To the contrary, the standard instruction is "here's what we got, but you should start with a lower charge and work up to see what you get-- just don't go further than this load."

!!! 100% agree. Many new reloaders treat manual's specs. as hard and fast formula. But in truth the listed specs. are "with EXACTLY this load, these are the results we got", and not "you must load exactly to this recipe".

In the front of a cartridge section, the drawing is usually SAAMI spec. and considered max....

 

[Nemo288]

\The only ammo that ever jumped crimp was in a 348 Winchester and that was because the expander button was a little generous and a smaller button solved that problem.\

Exactly my experience with an RCBS 445sm 3 die set.
They forgot to shave the expander stem. It was at .430".
As usual they were all over it and sent me a .427" stem.
No more loose bullets. RCBS rocks!

I have never had a bullet move either, even in heavy recoiling 44 magnum revolvers.
Personally, I believe the need for a HEAVY crimp is overstated.
Maybe any crimp in most rounds given good neck tension.
I only crimp lever rifle rounds down into the cannelure, not to it's bottom.
And am using a taper crimp more and more mostly to just iron out the bell mouth
and fold the mouth in slightly to smooth loading the gun.

I have a double rifle in 444. Weighs less than the Marlin 444s.
Kicks like some of the tales from the black powder bore rifle elephant hunting days.
I have tested bullet movement and have not been able to get a 300 grain cast bullet to move under recoil.
These are going 2100 fps.
I'll let you calculate the recoil fps in a 7.5 lb. gun.
Not earth shattering but it is at my personal limit.
My shoulder doesn't seem to be as flexible as my wrists and hands.

I am hoping some day to develop a 44 Alaskan based on the 348.
Basically a 450 or 500 Alaskan necked down to 44.
The gun will be at least 10 pounds. Maybe 11
Gary Reeder already has a round like this but I want the neck to be longer than what he has.
Some folks have modified the 444 by lengthening the action to allow longer COAL
and are getting almost the same performance as the 450-400 NE (or a 44 Alaskan).
I won't link to another forum but you can search for the Safari Grade 444 by Flat Top.

Sorry (but not too sorry) for the thread creep.

 

[H Richard]

When the bullet you are using might be the same weight, but the nose configuration could be very different. The taper of the ogive, the shape of the round nose (pointed or well rounded) Flat tip, hollow point of many different styles, all will change the OAL. Just seat in the crimp grove and/or the bullet MFG's specification. I once gave some bullets to a re-loader that were 95 gr, (for .380) but a regular RN, the loader looked up the load in his manual fo ra 95 gr. bullet (happened to be a Flat Point) and set the load to that OAL, and when I got them the bullet was seated way too deep, probably .050 too deep. I pulled all the bullets, saved the powder and reloaded them to the correct depth, after I went ahead and bought a set of dies that I hadn't wanted to buy. He won't ever load anything for me again.

 

[fredj338]

Is it more important to seat bullets to the load recipes cartridge overall length (COL), or to get the bullet inserted to be close to the forward edge of the cannelure?

I'm new to reloading so looking in my Lee #2 manual it says to have the case mouth near the forward edge of the cannelure for crimping. To get to the recipe COL I have to seat the bullet further out with the case mouth closer to the rear edge of the cannelure. I suspect seating the bullet to the recipe's COL is more important in order to keep pressure inline with the manuals published test pressure.

I am loading for the first handgun I've ever owned, it a new S&W 686 "Competitor" model 357 Magnum 6" barrel 6 shot cyl.

When loading revolvers, forget the oal, crimp in the crimp groove/cannelure, done.