C.O.L. Question

[Littledragon777]

I am reloading for .270 Winchester. I am Loading 57 grains of H4831 and using Hornady 130 sp bullets. My Hornady book shows an overall length of 3.210". The 130 bullets have a cannalure and if I seat them to the cannalure my C.O.L is 3.170". All the brass is the same overall length of 2.53". My question is do I seat then crimp on the cannalure as I have always done with my pistol loads or do I seat to the book recommended 3.210" and ignore the cannalure which just doesn't seem right. Also if I seat and crimp to the cannalure will that raise my pressure levels to high to be safe. Any comments would be appreciated.

LD

 

[Steve C]

For a bolt action or single shot rifle you can load to the manuals OAL without crimping as the bullet is usually held sufficiently tight by case neck tension alone. If you are shooting your ammo in a semi auto or pump action like those made by Remington that's more likely to slam the nose into the feeding ramp setting back the bullet, then crimp into the groove provided.

 

[Littledragon777]

I am loading for a Reminton Model 700. I was alway taught to load to the cannalure if a bullet had one so the shortness of the C.O.L concerned me.

 

[canoe on the yukon]

I am reloading for .270 Winchester. I am Loading 57 grains of H4831 and using Hornady 130 sp bullets. My Hornady book shows an overall length of 3.210". The 130 bullets have a cannalure and if I seat them to the cannalure my C.O.L is 3.170". All the brass is the same overall length of 3.53". My question is do I seat then crimp on the cannalure as I have always done with my pistol loads or do I seat to the book recommended 3.210" and ignore the cannalure which just doesn't seem right. Also if I seat and crimp to the cannalure will that raise my pressure levels to high to be safe. Any comments would be appreciated.

LD

The cannalure is provided as an option however crimping is not necessary on a bolt action rifle.Having said that,your numbers are incorrect.You need to recheck them.Case length is (max-2.540.....trim-2.530).Hornady lists overall length at 3.180 with that bullet.That would obviously match perfectly with your 3.170 figure if the case length they're using is 2.540 rather than the trim to length 2.530 that you're using.

 

[Skip Sackett]

Are you sure?

All the brass is the same overall length of 3.53".
LD

I could be wrong but, don't you mean the brass was 2.53" instead of 3.53"?

The minimum for that case is 2.520" and the maximum is 2.540". It would seem that you were right in the middle and life would be good.

The only thing I would say is this: Work up your load at this shortened OAL. It may be fine, it may not. I don't load for the 270 but I always load to the cannalure. If I want super accurate ammo, I don't use a bullet with one. All I do at that point then is make sure the case mouth is closed with a Lee collet die.

Hope this helps!

 

[shovelwrench]

Generally, I just seat to cannelure. Considering your only talking .040, and your still 3gr from max, I would'nt let it bother me. Considering max is a compressed load, 4831 is probably burning slow enough that you can't get enough in to max out on pressure. If your book shows pressures, notice the psi (or cups) for max is substantially lower then other powders. For me this reafirms that you can't get enough in there to pop it.

Really 4831 is more suited to magnum calibers because of its slow burn rate. You would probably have better luck with Varget, or 4895.

Remember though, this is the exact reason why your supposed to work up a load every time a component is changed, including bullet type.

 

[canoe on the yukon]

I noticed the 3.53 figure but I naturally assumed that to be a typo since it's a whole and exact inch.The trim to length I cited is quoted from Hornady.I'm aware that trim to lengths can vary somewhat.

As I said earlier,the cannalure gives an option.Since you're new to this,I'd suggest you keep things simple and seat to the cannalure.However many riflemen do "ignore"the cannalure for the very reason that many bullets do not even have one.Many will seat the bullet out farther in order to have it seated closer to the rifling,etc......but right now I don't think you need to muddy your mind up with any advanced techniques.

 

[canoe on the yukon]

Incidentely,with all due respect to a previous poster,H-4831 is excellent for your purpose.Varget and 4895 are much too fast to be efficient with this case and bullet.They will work but they won't be nearly as ideal as your H-4831.

 

[Littledragon777]

The cannalure is provided as an option however crimping is not necessary on a bolt action rifle.Having said that,your numbers are incorrect.You need to recheck them.Case length is (max-2.540.....trim-2.530).Hornady lists overall length at 3.180 with that bullet.That would obviously match perfectly with your 3.170 figure if the case length they're using is 2.540 rather than the trim to length 2.530 that you're using.

My book shows a C.O.L. of 3.210" not the 3.180" you mention. I am using the 7th edition and for bullet # 2730 my length of 3.17" would be .004 short. I am probably going to load to the cannelure and see if the cases show any pressure problems. I am guessing with 57 grains of H4831 which is about middle of the road I should be alright. I will probably use a light crimp, force of habit from my pistol reloading life. Thanks for all the info guys I really appreciate it. By the way I just broke my decapping pin so there will be a temporary lull while I send RCBS an order for some new ones.

 

[Littledragon777]

I noticed the 3.53 figure but I naturally assumed that to be a typo since it's a whole and exact inch.The trim to length I cited is quoted from Hornady.I'm aware that trim to lengths can vary somewhat.

As I said earlier,the cannalure gives an option.Since you're new to this,I'd suggest you keep things simple and seat to the cannalure.However many riflemen do "ignore"the cannalure for the very reason that many bullets do not even have one.Many will seat the bullet out farther in order to have it seated closer to the rifling,etc......but right now I don't think you need to muddy your mind up with any advanced techniques.

Your right about being new to rifle reloading but I have been reloading for pistol about 10 years but I do most of that on a Dillon 550b.. Also your right about the muddy mind as I just burned some chicken on the grill for the 4th as I was busy running down stairs to my bench trying to see what other trouble I can get in to. The wife appreciated that.

 

[canoe on the yukon]

My book shows a C.O.L. of 3.210" not the 3.180" you mention. I am using the 7th edition and for bullet # 2730 my length of 3.17" would be .004 short. I am probably going to load to the cannelure and see if the cases show any pressure problems. I am guessing with 57 grains of H4831 which is about middle of the road I should be alright. I will probably use a light crimp, force of habit from my pistol reloading life. Thanks for all the info guys I really appreciate it. By the way I just broke my decapping pin so there will be a temporary lull while I send RCBS an order for some new ones.

For the same reason that a case lengthens when fired,the COL will vary.The longer the case,the longer the overall length (when the bullet is otherwise seated the same).I do not have the 7th edition of Hornady's manual.I have 4 and 5.With that bullet,#4 shows an COL of 3.200 and #5 shows 3.180.That is all with the bullet #2730.The boat tail (27302)shows 3.225 in the #5 manual.

The point that you need to focus on is that the OAL will vary with EXACT case length which will VARY.The cannalure is several thousand's from top to bottom which will make the variance potential even greater.

Your load of 57 gr of H-4831 behind that bullet is quite moderate and a few thousand's seating depth difference will not materially matter.

About crimping....you don't need it in your application.Those who tell you to do it are uninformed except where it's actually needed.

 

[Littledragon777]

For the same reason that a case lengthens when fired,the COL will vary.The longer the case,the longer the overall length (when the bullet is otherwise seated the same).I do not have the 7th edition of Hornady's manual.I have 4 and 5.With that bullet,#4 shows an COL of 3.200 and #5 shows 3.180.That is all with the bullet #2730.The boat tail (27302)shows 3.225 in the #5 manual.

The point that you need to focus on is that the OAL will vary with EXACT case length which will VARY.The cannalure is several thousand's from top to bottom which will make the variance potential even greater.

Your load of 57 gr of H-4831 behind that bullet is quite moderate and a few thousand's seating depth difference will not materially matter.

About crimping....you don't need it in your application.Those who tell you to do it are uninformed except where it's actually needed.

Thanks again for the comments. I guess I am use to crimping when I load for my 44 mag and 357 as the bullet will creep without a good crimp on it. You are correct on the cannelure width and if I seat to the bottom of the cannelure that should add a a little more length to get me closer to the recommended length of 3.210".

LD

 

[canoe on the yukon]

Thanks again for the comments. I guess I am use to crimping when I load for my 44 mag and 357 as the bullet will creep without a good crimp on it. You are correct on the cannelure width and if I seat to the bottom of the cannelure that should add a a little more length to get me closer to the recommended length of 3.210".

LD

If you will re-read,you will see that the #4 manual gives a COL of only .010 less.Do you know PRECISELY what the case length is that they're using?I don't.It could be anywhere from the min to the max.When you say "the recommended length",you are obsessing about something that is too minute to matter.

In some areas,a few thousand's matters.In this area,it's far too trivial to concern yourself with.As a matter of fact,you will probably note a few thousand's of difference between cartridges that have gone through the same seating die.You're obsessing too much about nothing.Your rounds with an OAL of 3.170 WILL DO JUST FINE!!!!!!!

 

[Skip Sackett]

That's OK, sometimes I obsess too!

Hornady 130 sp bullets. Any comments would be appreciated.
LD

LD,
There have been times in my life where I obsessed too. I am one of those kind of guys that "just has to know why." You seem to be the same kind of fellow. Nothing wrong with wanting to be sure about something. It gives you piece of mind to know "how come?"

I don't have the Hornady manual you mentioned. One thing I wanted to ask though was: "Do you have the EXACT same bullets they are using in the recipe?"

If not, that could be part of the problem. A bullet with a more rounded ogive will seat to a different OAL and still be the same weight. It is possible too that their bullet has changed minutely as all things man made have tolerances. When two parts at the top of a tolerance are combined you have problem "X", put two parts together that are at the bottom of their respective tolerances and viola, you have problem "Y".

In reloading you have tolerances too. Minimum and maximum case length, yada, yada, yada.

I have loaded pistol bullets that stuck in the case a difference of .030" from the usual bullet I used to have the velocity increase over 150fps, almost 200fps to be honest.

The part that sticks out of the case, making the OAL is not the problem. It is the part that is in the case that is the problem. Look at this picture:

Both of these bullets are the exact same weight. Notice the ogive. One is much more tapered than the other. If I seat them to the same OAL then the longer bullet has more in the case. That can be a problem, or not, depending on other factors, such as powder charge and interference with the rifling.

In my light target loads with these 45ACP bullets its not going to matter. Change things around a mite, go to some of the high pressure 38spl loads I am known to run, and it might make all the difference in the world.

As for crimping rifle bullets, it isn't needed if all you do is shoot from a bench at paper. If you are going afield, are going to be encountering rough hunting conditions or are using your ammo in a tube magazine (not for the the 270 but others)or in a semi auto rifle, it is recommended in most loading tutorials to use a firm crimp.

Without belaboring a point, if you start at the low end of the data for the powder and work your way up, you should have no problem with the reduced OAL.

If it was me, I would load up a few, 5 or so, and run them over the chronograph. If they are in the neighborhood of what the book says a minimum charge should run, you should be able to work up from there. If the velocity is higher at those loads, you may/will have to stop before you reach the top of the printed data. That will be a win/win for you. Maximum velocity with less powder. What could be wrong with that?

 

[Littledragon777]

Thanks Skip, I appreciate your comments. I to have noticed the difference in length on many of the handgun rounds I load. Since I don't load anything near max but stick around the middle if not lower end of the range when punching paper I feel safe with my loads. A good example is I usually shoot winchester 158 gr jhp's in my 28-2. I use only 5.5 grains of AA#5. I have not been able to get any 158 winchester for some time now so I am loading Zero 158 jhp's. The Zero is a slightly longer bullet but with me loading to the cannelure I am still within specs of my case gage. So instead of changing my dies I just load as usual knowing that I am not out on a limb so to speak. With my autos I usually seat to the same depth check them in the case gage and then check to make sure they will cycle correctly. Once again I am well under any max load levels and usually there is only a few thousands differece between the 2 bullets. Usually the biggest thing I notice is that one of the bullets is larger in diameter than the other brand and will leave a bulge circle all the way around the case where the base of the bullet lies. While these sometimes don't fit inthe case gage all the way they are then checked in the barrel of the handgun in question and they have all fit usually with room to spare.

You are right I am the kind of guy that always wants to know why something works or doesn't work, even if I don't fully understand it there is usually a learning from it.

LD

 

[BruceM]

I want to state up front that I load almost exclusively for a turnbolt and not a pump, autoloader or lever gun.

Having said that, the overall length and the presence of a cannelure or lack of it means almost nothing to me. The first thing I do is build a dummy round with a sized & trimmed case and the bullet I will be using. I almost invariably get the best accuracy when bullets are seated out so that they are almost but not quite touching the lands of the rifling. There are now a number of tools you can buy to give you this dimension but before their appearance, I just seated the bullet out & smoked it with a wood match, candle or even sight black. If I could not close the bolt without the bullet touching the rifling, it was seated slightly deeper (1/8 to 1/4 turn of the seater plug), resmoked and the process repeated until there are no marks from the rifling on the smoked bullet. Then the seater plug was turned in 1/4 turn deeper, the bullet smoked and the round double checked.

After this process, the loaded dummy is inserted into the magazine and the bolt cycled in order to insure that all further completed rounds will fit in and cycle thru the magazine. After this check, the OAL is recorded and load development proceeds.

This procedure allows for maximized case capacity and minimum bullet jump before it engages the rifling. Obviously, if you are loading for a repeater which has a tendency to push bullet deeper into the case or a heavy recoiling rifle which does the same, you must use bullets which can be crimped but in a .270-.30-06 class bolt action rifle, its usually a non-issue.

Incidentally, H4831 is THE classic propellant for the.270, especially with 130 grain bullets. Jack O'Connor, the biggest proponent of the .270, had one favorite load using a 130 grain bullet & 60.0 grains of H4831. This should be considered maximum. Hodgdon's on-line data shows a 56.0 grain starting load with a 60.0C grain max. I personally use a Remington case, CCI magnum primer, Sierra 130 grain spbt and 59.5 of H4831.

For what it's worth.



Bruce