30/06 Col

[kungfustyle]

Hello,
I need some help with my col on a 30/06. I have a Lee gc'd 200g lrn that I have sized at .309 over 23 to 25g of SR 4579 powder. The cast Lyman handbook lists col at 3.25 however I looks like the round is engaging the lands to about .58 down the lead of my dummy round. Is this cool or what should I do? I've loaded an 8mm Mauser w/ great success and now I'm turning my attention to my 06. The Mauser didn't have any of these problems but it is only about 175g lrn. Thanks for the help.

[Char-Gar]

There is no way you can pick a cartridge over all length out of a book and use that number for a cast bullets. There is way to much variance in bullets, alloys and rifles to do that.

You are on the right track using a dummy round. Without a picture of the dummy round and the makes the rifling makes on the bullet, I would not venture a guess at whether you are OK or not.

[Lead Fred]

Several companies make OAL gauges.

Get one, and leave the guessing to someone else.

The gauge uses a dumby cartridge that you put the boolit you are using on the end of it.

You stuff it in the bore, tighten it up, then pull it out and measure your OAL per your rifle and boolit.
Subtract freebore, most use .005 to .010, SAMMI spec is .020. which is way too far for most rifles.

http://www.hornady.com/store/OAL-Gauges/

The curved is for semi-autos, the straight is for bolt guns. The prices here are way off. you can get them way cheaper if you look

[kungfustyle]

Made another dummy round and had the lead it free flowing in brass, chambered it and it was 3.161. Now with pistols you pay attention to the col. Is it OK to start here at 3.159 w/ a minimum load and work up?

[Ben]

kungfustyle :

So many reloaders think the the Cartridge Overall Length given in loading manuals is the " Gospel.".

WELL , IT ISN'T THE GOSPEL ! !

Different chamber reamers are used by gunsmiths and different manufacturers of center fire rifles. It isn't unusual to see differences in the COL from rifle to rifle, in the same caliber.

If you'd like to establish the correct COL for your current cast bullet and rifle combination , here is the procedure :

(1)

For safety reasons, take an empty F/L sized case ( no primer, no powder ) that chambers smoothly with no bolt closure resistance in your rifle.

(2)

Now.....seat your cast bullet out much farther than you think is needed in this " dummy round " that you are making.

(3)

Most likely this " long seated dummy round " won't chamber smoothly in your rifle.

You may now take your bullet seating die and begin turning the seating stem about a 1/4 th of a turn at a time downward and then try again to see if the bolt will close on your rifle. By trial and error continue this process checking the round in the chamber of rifle to see if the bolt will close. ( DO NOT FORCE THE BOLT CLOSED, stop and remove the dummy round if you feel ANY resistance on the bolt handle when you are trying to close the bolt )

(4)

When the bolt is just about to close, change the 1/4 turn downward to 1/8th of a turn downward on the seating stem of your bullet seating die.

(5)

When the bolt closes with little or no resistance, you have the CARTRIDGE OVERALL LENGTH for your particular rifle and your own particular cast bullet style. You now have minimum " bullet jump " into the rifling of your rifle , a condition that many cast bullet rifle shooters find desirable.

You can set this " dummy " aside for future reference when you are trying to establish the COL for your rifle and that bullet on another day . Many reloaders write or type the caliber of the rifle , the make of the weapon, The model of the weapon and the cast bullet style of the bullet along with the COL on a label and tape it to the dummy round that you have just finished making.

(6)

Any other ( different ) cast bullet style will require you to do each of the steps above a 2nd time and obviously you'd end up with a different COL for that cast bullet style.

Ben

[Green Lizzard]

i like bens way, on some guns it works best if the bolt is striped (cocks on closing)

[725]

#2 way to find a c.o.a.l: Check that the gun is unloaded (Just had to say that). Take a flat ended rod and insert it in the muzzle all the way down to the bolt face (needs to be cocked so the firing pin doesn't interfere) Mark the rod at the muzzle with a piece of masking tape. Open the action and drop a boolit into the chamber just hard enough to make a friction fit (ie: very light). Take the rod again and reinsert it into the muzzle down to the boolit. Mark the rod at the muzzle again with the masking tape. Tap out the boolit. Now, your rod has marked on it with the masking tape the overall length of a cartridge that fully engages the rifling. Back your c.o.a.l. off by whatever length you want. Boolits for me usually get right up there almost touching the lands and grooves. Jacketed gets backed off .0020 - .0040 or so. Testing c.o.a.l. gives me the most accurate answer for a particular gun/case/boolit combo.
I've done it Ben's way and once in awhile, I've moved my boolit in the case and was unsure of my final product.
Have used the commercial tool for this and have ended up preferring my method to all others.

[fourarmed]

Actually, you don't even need the second piece of masking tape. Run the rod down against the tip of the bullet, and use the inside jaws of your caliper to measure from the barrel crown to the first piece of masking tape. Lay the caliper on the bench and put a case and the bullet beside it. You will immediately see if the bullet has a chance of working. Some have to stick 'way down past the neck - they might work, but probably not - and some don't even reach the mouth of the case. They definitely won't work. A quarter-inch brass rod will work fine.

[kungfustyle]

OK, Here is a range report for those interested. I followed 725's advice for the 06, my 8mm Mauser and My Mosin Nagant. The Mauser and the Mosin both came up w/ the same col that the Lyman cast 4th, funny same gun's they used.....Now on to the 06. Mine came out to 3.15 so I took .02 off and went w/ 3.13....Started w/ 19.5 g of SR4759 and went up one grain from left to right w/ a finish at the upper right corner at 25.5g. I used Alox and sized the 200g rn at .309. I've slugged my barrel and it comes out to .309 so I ordered .310 sizing die.....So I don't know if the accuracy was off due to leading or what but the first two groups you can cover with a dime. Cleaning wasn't over the top but there was a fair amount of lead. I've tried pan lubing w/ Darris 50/50 paraffin and Vaseline and STP works great for the Mosin and Mauser no lead today. Each was 3 round s except the 3rd group I let a friend shoot. The lead tests at 17Bnh. Thanks for your help...Jeff84023