Bullet seating depth

I looked for this in the archives but could not find it.

A box of factory shells broke the 100.00 mark so I'm biting the reloading bullet. I purchased a RCBS master kit and familiarized myself with all the components. Everything was great right up until I got to the COAL. The manual gives a rule of thumb measurement which is .045 different than a factory load, but says this measurement needs to be taylored to my gun. I'm reloading my Wetherby 30-378 which I understand has a free bore chamber. So where does a guy start on bullet depth???? If this is a dumb question, please be gentle.

Welcome to the Guide, balzout.
The only dumb questions are the ones you are too proud to ask. We all started at square one.
Start with the COAL that the bullet maker recommends and see how it shoots. That will do to work up your initial loads. Measure the groups at the best charge level. When you are testing, I suggest you shoot 5 shots per group, not 3, and you'll probably have to stop often to let the barrel cool with the bolt open. You don't want it to get so hot that you can't comfortably lay your hand on the warmest part. (An old Marine I know always said that if you wouldn't want to touch ...."a certain tender part of your anatomy".... to the barrel, it's too hot to get good data. That wasn't exactly the way he put it, but I'm sure you get the idea. :mrgreen: ) The reason is that your POI will shift as the barrel heats and changes shape, making your data worthless. Bring another gun or guns :D to play with while you wait, the hotter the weather, the longer you have to wait. Weatherby cartridges will generate a lot of heat with their huge powder charges.

Then, if you want to experiment, make up a dummy cartridge (no primer, no powder) with the bullet seated out as far as you can. Try it in the action and see if the bolt will close. (Likely it will not).

Note: The chamber's max COAL and the magazine's max COAL may be different, so check to make sure it will feed OK from the rifle's magazine. If it does not, follow the steps below until it does, then see if there is enough of a difference in group sizes to warrent the longer COAL. Often there is, but sometimes there isn't. The only way to find out is to actually test it in your rifle. Some rifles are very sensitive to minor differences in COAL, others don't seem to be effected enough to matter. They're all different.

Adjust your seater to set it .005 deeper and try it in the action again. Repeat until the action will close, then put the dummy aside and load a few rounds to see if they group better than at the listed COAL. If they do, back off the COAL in increments, load a few rounds each time and shoot them to see what affect it has on the group sizes. If the max length is the most accurate, crimp the bullet in place and use it to reset your seating die, if not, reseat the bullet at the most accurate depth and crimp it. Save (and label) the dummy. You will likely want to be trying other bullets to see what your rifle shoots best, and each one will be different.

There are tools that make this easier (Stony Point makes a good one), but above is the basic procedure we used before such tools came onto the market.

The most important investment you can make at this point, though, is at least two more current loading manuals. You got the Speer with your gear, I would suggest that you add the Sierra and Lyman (or Hornady or Nosler or Lee). They will all give you a lot of information that you need to know, plus they will give you the ability to evaluate loads you come across on the net by comparing them to the published data. Don't expect them all to agree 100% - rhey won't. Different rifles and components will give varying results - they won't usually vary by a lot, but if they do you will generally find that two agree closely and you can trust that.

Amen on the barrel heating. I have a Stevens in 300 Win Mag. The first two shots do great, the third is aways a flier.
Dean
PS Oh, and welcome to the group.
[smilie=w:

Thanks for getting back to me guys.

When I started this process, I was under the assumption that I was going to set the COAL at .050 to .005 off of the rifling. I continued to make dummy loads until I was .200 longer than factory loads, both the magazine and the action were ok with this. .200 longer looks REALLY long and this is when I realized I didn't know what I was doing. Up until then I was a master at reloading with only one day of experience.:mrgreen: How long could I have gone, I don't know. My rifle is free bored at least this amount.

I guess my question now is, if I do use either a factory load or some other published COAL number, I reload to find my best group and then change the bullet depth (how much change is change, .002, .020 ?) and start the process all over again? Or is there a rule of thumb on the Wetherby's as far as bullet depth off of the rifling? Thanks again. Larry

Using a factory load, unless you know what brand of bullet was used, is not the way to go. SAAMI spec is the max COAL for factory ammo to insure it will work in any rifle. For a specific bullet, you start with that manufacturer's specific COAL for that bullet. When you find the most accurate charge level for the powder, then start playing with your COAL. You only need to start over when you change bullets (even if they are the same weight). You might end up at the same charge, but always start over (or back off the charge 10%) when you change any component. Sometimes that 10% will put you lower than a starting load, depends on the cartridge.

Weatherbys have been manufactured by several different companies over the years, and their specs have changed over time. It's always a good idea to start with the idea that each rifle is a universe unto itself. Two identical rifles with consecutive serial numbers might have the same max load and prefer the same combination of components, or they can be completely different. There is no way to predict it, you just have to experiment to see what you've got to work with. In general, (not true in every case) Weatherby's I have known have been fairly user friendly with regards to COAL, but one of them has been extremely picky, so much so that .01" difference in COAL was the difference between a sub MOA group and a shotgun pattern. I almost gave up on that one, but it was very accurate with factory ammo, so I knew the potential was there and I kept at it. Still, it took about four boxes of bullets to work a good load up for it. I don't own any Weatherbys and in fact own no magnum rifles right now, but it's hard for me to resist a "betcha you can't find an accurate handload for this rifle" challenge. I hate heavy recoiling rifles, but I go through more than 10,000 primers in an average year, so I do NOT want to develop a flinch. It was the owner's shoulder that took all the abuse of load testing. :mrgreen: The downside of magnum cartridges is that case life is usually pretty short - maybe five loadings, sometimes more, versus over 20 for regular cases.

Thanks versifier, you make it sound easy. I'll pick up some more manuals asap.

I was playing around with some lengths last evening and the triple shock bullet that I am reloading doesn't lend it self to be put at just any length. This particular bullet has four grooves cast into the shank of the bullet that only have about a .050 surface area for the end of the brass to land on. The factory loads completely cover all of these rings and the next avail. length would be .050 longer and for .050. I'm assuming that the end of the brass needs to land on the shank of the bullet to be properly crimped. Maybe I should have phrased that as a question instead. Even when you leave the bullet sticking out long enough to expose a groove, there is still about .065 of the bullets tail hanging into the case, so its not like there is not 100% brass/bullet contact. Would this be an optional COAL or completely forbidden. Like I said prior, my gun would be fine with this or even longer. Thanks Larry

TSX's are solid copper and you need to use the loading data from Barnes for them. So one of the manuals you need to order is the one from Barnes. Powder charge weights are different for them than for conventional lead alloy core bullets.

The design does limit your ability to choose optimal COAL - you will have to crimp on the driving bands - but there is still room for you to play with. Conventional crimp dies can make this an exercise in frustration - I often have to deal with it loading cast bullets with thier lube grooves. I suggest you have Lee make up a custom Factory Crimp Die for you. They are not very expensive and the turnaround time is only a few weeks. Go to www.leeprecision.com and look up custom orders. They will need you to send them a dummy cartridge. They have made several for me for uncommon and wildcat rounds.