C.O.A.L.???

[skyking897]

I'm very new to reloading, in fact, I've only reloaded 15 rounds of 45-70 gov't. Done a fair bit of reading and watched countless videos on the subject and everyone seems to gloss right over the cartridge overall length. I understand you don't want to be longer but what are the consequences of being shorter. I trimmed the 30-06 cases to the proper length 2.494" and used a 150gr. jacketed bullet (boat tail I believe it's called). When seating the bullet to COAL 3.340" the crimp groove (can't remember proper name) is no where near the end of the brass. I seated one round to the groove and it measured 3.204". That's 0.136" shorter than specs. Did I use the wrong bullets, am I doing something wrong or is it ok to be shorter?

[Stumpkiller]

The only concerns of shorter are, depending on the action, feed issues. Unless you are crimping the crimp groove can be ignored.

The maximum COAL is a handy benchmark for ammunition and firearm makers - but you can be under or over. It's one dimension to tweak for best performance with a given bullet.

And sometimes you do want to be longer than COAL; or at least can be. Chamber throat and jump to the lands may favor less bullet in the case.

[Robinhood]

Different bullets will have a different COAL. A 150 grain will almost always have a shorter COAL than say a 180. Most Reloading manuals that list your bullet will give you the suggested COAL. COAL is a little more complicated than one length for all bullets in a given cartridge. Guys looking for extreme accuracy work with a different measurement, CBTO Cartridge Base To Ogive. First one needs to know where the lands are. Then they will make adjustments to put the bullet ogive the desired distance from lands. Most hand loaders load it to the manufactures suggested seating depth.

[Marine]

Going too short can build dangerous chamber pressures so use caution when going shorter than the bullet makers listed coal likewise jamming into the lands will raise pressure.

[69gen1]

3.340 seems long to me in my speer #12 for 150 gr the coal are shorter than what you you are using at that leingth..what books are u useing to get your data..do not load till you have sufficient data to go by and start low and work up the charge

[69gen1]

Most powder company's have data online like hodgen and others.i use multiple sources and compare before I start...and robinhood up above is right..different bullits and varying weights and manufacture have different coal

[skyking897]

3.340 seems long to me in my speer #12 for 150 gr the coal are shorter than what you you are using at that leingth..what books are u useing to get your data..do not load till you have sufficient data to go by and start low and work up the charge

I'm using the Modern Reloading manual by Lee and have a copy of One Book/ One Caliber ordered. The 3.340" is given with all the other specs for the 30-06 cartridge but after rereading it I've found a minimum spec of 3.200" for the 150gr. bullet listed along with min/max powder loads etc. I've looked at a couple of sites but did not find any info on a minimum length. Right now I'm waiting for my manual to be delivered and will try to verify the info on other sites too.

[69gen1]

I'm using the Modern Reloading manual by Lee and have a copy of One Book/ One Caliber ordered. The 3.340" is given with all the other specs for the 30-06 cartridge but after rereading it I've found a minimum spec of 3.200" for the 150gr. bullet listed along with min/max powder loads etc. I've looked at a couple of sites but did not find any info on a minimum length. Right now I'm waiting for my manual to be delivered and will try to verify the info on other sites too. hodgenreloading.com. very good resource for load data

[skyking897]

hodgenreloading.com. very good resource for load data

link doesn't work.

[Stumpkiller]

http://www.hodgdonreloading.com/node

Two "d"s in Hodgdon.

[Dave Hoback]

Nm

[PhilC]

I'm very new to reloading, in fact, I've only reloaded 15 rounds of 45-70 gov't.
Stumpkiller and Robinhood gave some good advice!

I think we should be helping him understand the basics of producing ammo without going into advanced techniques like CBTO, bullet ogives, jumping to or jamming in the lands, etc.

COAL is fine for someone "very new to reloading" who admits they've only loaded 15rds of a straight walled cartridge and there's nothing at all wrong with loading that way until they gain confidence and experience. I was a COAL "reloader" for about 5yrs years before getting into more involved loading practices. Took my first deer with a COAL "home load" and several more after that, one at 350yds (7RM w/Nosler 150BT in 1988). I knew nothing about ogives, distance to lands, CBTO, weight sorting, runout, etc. COAL works and quite well.

My recommendation for skyking is to tell us what specific bullet you're using so we know you have the correct COAL. You'll need to understand that, due to manufacturing processes, bullet length will vary even within the same batch/box and most definitely between manufacturers. Case in point, a 30cal 150gr made by Speer may not, most likely will not, have the same COAL as a 30cal 150gr bullet made by Sierra, Hornady, Nosler, Berger, Barnes, etc.

Here's my advice, select a handful from the box of bullets you're using, enough to be a representative sample (15% - 20%), measure each one and record the length. Now, using those numbers, calculate the average base to bullet tip length, find a bullet out of your box that's closest to your calculated average, set it aside and use it to set COAL for that specific box of bullets. Understand your COAL will vary some due to base to tip length variations but most likely won't affect accuracy of that box of bullets unless you find a few that are significantly different (+/- .020") than the average.

There are all manner of advanced techniques, but if your primary focus is producing good hunting ammo, a whole lot of it won't matter unless you're planning to consistently shoot in excess of 350yds. IMHO, unless or until you're ready for that, stick to the bullet manufacturer's recommended COAL as published in their specific recipe, and keep this in mind, changing any one of the recipe components can change everything.

;)

[skyking897]

My recommendation for skyking is to tell us what specific bullet you're using so we know you have the correct COAL. You'll need to understand that, due to manufacturing processes, bullet length will vary even within the same batch/box and most definitely between manufacturers. Case in point, a 30cal 150gr made by Speer may not, most likely will not, have the same COAL as a 30cal 150gr bullet made by Sierra, Hornady, Nosler, Berger, Barnes, etc.

Don't believe I mentioned but I inherited this gear (and a 30.06) from my uncle. All the bullets he had were Nosler or Hornady except for this one unbranded box which just said "30 cal. 150gr. FMJ" must be about 500 bullets in it. I would sit with him sometimes while he reloaded so I know he used these in his 30.06 for at the range. If I could figure out how to post a picture here I could show it looks like/matches a Sierra bullet. I know that's not the recommended way to identify bullets. Anybody has "One book/One Caliber" for 30-06 on page 41 #2115 bulllet (top of page) matches what I have.

[skyking897]

http://i67.tinypic.com/2valezd.jpg
Picture of page in book and bullet.

[Stumpkiller]

There are various 150 gr FMJBT that all look very similar.

Hornady looks pretty identical to the Sierra
https://media.mwstatic.com/product-images/880x660/Primary/733/733374.jpg

By the way - DO NOT use the powder loads from that page/section in your .30-06!

The .30-06 Ackley Improved has a blown-out 40 degree shoulder and is capable of holding more powder at suitable pressures vs. the regular .30-06

[PhilC]

Very good advice above.

[skyking897]

I hadn't planned on using the loads for the Ackley bullets, was just trying to ID the type of bullet and that picture was the closest to what I have. Stumpkiller, your picture of a Hornady bullet looks identical to what I have. From my uncle's notebook he used either 48.5 gr. of IMR 4064 or 47.5 gr. of IMR 4895 powder for this bullet to use at the range.

[reddeluxe]

A great deal of sound reloading advice in the posts above. Agree the reloader's manuals and bullet manufacturers will have good, safe C.O.A.L. dimensions to follow for starting loads. As more experience is gained, the OP can learn to play with seating depth....some barrels prefer to have the bullets jumped, some like them just kissing, some like to be jammed into the lands, for best accuracy. Just be aware bullets seated TOO deeply will eat up available powder capacity, and those seated TOO long will not have proper neck tension and poor concentricity....in extremes both can be dangerous. In my experience, most factory chamber throats are cut on the generous (long) side, as far as throating/and/or freebore to accommodate the greatest range, from light to heavy, of bullet weights available for a specific caliber. Just one of the many variables to experiment with when tailoring ammunition to a specific firearm. Be safe and have fun.