[BigTiny274]

I loaded up some 300wm's last night with Hornady SST's. I set the bullet down to the grove and my COL ended up to be 3.334, instead of 3.340. How much will this make a difference? I am using RL-22 and 77g I think it was. The case is also crimped with a Lee die.

Thanks

[ocabj]

Cartridge overall length isn't a very good way to measure for consistency since the tips of bullets tend to vary. A .006 variance isn't going mean anything as far as safety is concerned for this cartridge. Accuracy maybe, but doubtful.

You should get a bullet comparator so you can measure your rounds based on the ogive, not the tip.

[BigTiny274]

Does Midway have something like this? What is ogive? I looked at my caliper and it didn't look like that little bit of difference would matter any, but I wanted to check here first before I went out tomorrow and did my shooting.

[ocabj]

http://en.wikipedia.org/wiki/Ogive

For the sake of bullets and reloaders, the ogive basically begins where the curve of the bullet begins. The ogive is right where the diameter of the bullet begins to shrink as it tapers to the tip.

This is important because where the ogive is on a loaded cartridge with respects to the beginning of the barrel throat when the loaded cartridge is chambered into the rifle has a great deal of impact on accuracy. You hear about how a lot of handloaders load close to the lands to increase accuracy. This means they seat the bullet to a depth such that the ogive of the bullet is anywhere from .001" to x" amount of inches away from the lands (when the bore begins). The amount of distance to seat your bullets from the lands for optimal accuracy is going to be unique from rifle to rifle, barrel to barrel.

Midway should sell bullet comparators. Personally, I use the one made my Sinclair Intl: http://www.sinclairintl.com/cgi-bin/category.cgi?category=RESDTCO&item=09-700&type=store

A bullet comparator by itself is useful since you can measure your loaded rounds to make sure they all have same length from the base to ogive. This is the best way to make sure your cartridges that you are loading for that one batch are all the same 'length'. Measuring the cartridge from base to tip, can be inconsistent by nature since many bullets will have imperfect tips, especially open tip match or hollow point bullets. Even bullets with polymer tips like the Hornady A-Max or V-Max line will not have perfect tips.

But in combination with a tool such as the Stoney Point OAL Gauge (http://www.stoneypoint.com/oal_index.html), you can optimize seating depth for your rifle.

[LDBennett]

For a beginning reloader you should follow the "recipe" exactly. When you fully understand all the principals of reloading you can then deviate from it.

Your 0.006 inch shortness will do virtually nothing but if you errored in the wrong way you could get the bullet jambed into the rifling when you close the bolt and the pressure could go up astronomically. Just as bad, when you try to remove the un-shot cartridge the bullet might stick in the barrel, the case will come with the bolt and the powder will dump into the action. Nothing short of a cleaning rod and a hammer will remove the bullet stcuck in the barrel. The "correct" cartridge length as listed in the recipe assures it will work in 100% of all guns made to the industry standards for that particular cartridge. Each recipe is thoroughly test in test barrels with pressure sensors and the safety of each recipe is assured by the manufacturer of the manual. That's safety that should not be discarded readily. A reloading mistake can hurt both you and the gun! So follow the recipes exactly for now.

Reading is the key to understnading. Buy several reloading manuals from major bullet and powder manufacturers. Read the "how to" sections of each and try to understand all aspects of reloading. Do several manuals as each gives a different view point of the same info and one of them may just turn on a light bulb of understanding. Beside we learn through repetition. I think the Hornady manual is particularly good in this respect as it has some very good drawings to illustrate the process and the results of mistakes in reloading. But I own about 15 manuals both old editions and the newest editions. You can not get enough education!

LDBennett

[4fingermick]

I get a flat based bullet and push it gently into the mouth of an EMPTY unprimed case and carefully close the bolt on it. The bullet will be stopped by the rifling and when you pull it out you will be able to use this as a guage to see how far various rounds are from the rifling by comparing the loaded round against it. If you have more than one rifle in any calibre, make sure you mark it clearly. Keep this in your Vernier caliper box. Common sense and a vernier will do you at this stage.
Mick.

[LDBennett]

Another method that is accurate enough (but not perfectly accurate) is:
*close the bolt of the rifle--empty chamber
*slide a cleaning rod with a flat end piece on it into the barrel and touch the bolt with it
*mark the rod with a ink marker holding the marker vertical to the bore
*seat the bullet of choice very long into a case
*put it into the chamber and gently push cartridge in with you finger until it just stops as the bullet hits lands in the barrel
*mark the rod with a ink marker holding the marker vertical to the bore

The distance measured with a vernier calipers between the too marks is the absolute Maximun overall case length you can ever use with that bullet. Each bullet type and manufacturer you use must be measured this way. I also suggest you only approach this max length to no less than 0.002 inches shorter. Many loading recipes in loading manuals recommend overall lengths up to 0.060 off the lands but most guns shoot better when the bullet nearly touches the lands (touching the lands is the measurement you just made). So always make the overall cartridge length less than what you just measured.

There are various tools that allow you to do the same measurement as above but I always do this one as a verification of the other tools results as i often find the tools can give misleading results because the lands are chamfered where the Ogive of the bullet touches them in any measurement of max overal length.

LDBennett