How do you figure you O.A.L starting point?

I have reloading manuals

-Robb

Try this; http://www.bergerbullets.com/vld-making-shoot/

I look at a manual.

If I'm concerned primarily with accuracy (i.e. no hunting or use of magazine) I use the Hornady OAL gauge with the appropriate modified case to see how far a given bullet needs to go to get to the lands. I then back off from there for load testing and experimentation to find the optimum cartridge length.

If I need the rounds to work in a magazine (the above process tends to produce rounds that are too long for a magazine and I use rounds made using the above method as single shot mode model only) Then I rely on the OAL that is listed for that load in my manual.

I use 3 limiting factors.
At least One bullet diameter in the case.
Magazine length.
The rifling.
This is my order of importance.

I have a notch in the neck of an empty case, place the bullet just barely in, load into chamber, remove and measure COAL. Take an average of at least three measurements.

Do it for all calibers, each firearm and for each projectile. Sometimes the magazine determines my max COAL.

Your method works well too, Jeff.

otisrush said:

If I'm concerned primarily with accuracy (i.e. no hunting or use of magazine) I use the Hornady OAL gauge with the appropriate modified case to see how far a given bullet needs to go to get to the lands. I then back off from there for load testing and experimentation to find the optimum cartridge length.

Click to expand...

That is how I do it also.

Bolt lift method. The cleaning rod method works also, but is dependent upon how precisely the user marks the rod at the muzzle - did the blunt tip approach the muzzle at the exact same angle for both marks? If 5 people did it 5 times each, will you get 25 identical results to within 2thou? Modified cases, depth spindles, and comparators also work. Smoking a bullet also works, slitting a case neck also works. But out of all of the methods I have tried, bolt lift gives the most consistently repeatable result.

Sinclair seating depth tool. Start .025 off the rifling, and move the bullet out .005 at a time until .005 off the rifling.

For varmint and target loading. For hunting and practice ammo, I use same oal as similar factory ammo. I don't need 1/2 MOA for ammo to be shot standing offhand.

Walkalong said:

I have done it this way and used a comparator, prefer bolt lift. Won't work with heavy neck tension or way to light neck tension.

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What trouble have you had with too much neck tension for bolt lift method? I generally use too much on purpose to help reduce how much the test itself will forcefully seat the lands. Only negative consequence I have seen is when a guy collapses the shoulder via repeated, deeper and deeper seating of the bullet. Too little neck tension can also work - as long as the bullet isn’t getting pulled and stuck in the rifling. I measure my BTO before and after the test to confirm the bullet hasn’t been further seated - or at least capture how much.

338reddog said:

With the bolt lift, how are you obtaining neck tension?

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Full length or partial length neck resize (not to be confuse with full length case sizing vs. neck only sizing) can be done with a standard die. For those of us with bushing dies and expanding mandrels, well, we can pick our neck tension.

I begin by using the factory cartridge length/taper crimp to start with. Next I work up a good load at that setting. Then I move the bullet in or out tuning for further accuracy. For rifle I will try both crimped and uncrimped also looking for accuracy. I also will try more or less taper crimp on ammo that uses it seeking better groups. I have not been one that primarily chases the lands for accuracy either. YMMV

There are lots of ways. One simple way is to load a bullet into an unsized case, using toilet paper to hold it in place. Chamber the round slowly, feeling the bullet make contact with the lede. Don't force it -- go gently. Then withdraw the case and measure it.

Rat Robb said:

I have reloading manuals

-Robb

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A reloading manual is a guide. Especially with OAL. Finding your max OAL for you rifle and knowing how far you are working off the lands is good not bad. It also has nothing to do with a reloading manual.

I will find my max OAL where my projectile of choice touches the lands and back off at least .020. Some rifles have long throats and have to be further than That. Compare to the manuals OAL and if it ia shorter I will not go all the way to max powder charges. Due to decreased case volume. A little longer and you MAY be able to get a little extra powder in there. But you have to work up slowly.

I find a dowell works better than a cleaning rod to push the bullet when finding the OAL. It is lighter and knocks the bullet out more gently.

Just going by the manuals OAL could be dangerous if your rifle has a short throat and the manual lists a projectile with a different ogive than the one you are using.

Sorry for the long post but this is important stuff. Good luck and be safe

A bullet comparator will save you some time by not having to test each projo you want to use .

The first thing I do is determine what my MAX OAL is with the bullet I'm using. I log this in to my book for further reference. I have several guns with min spec chambers that can not use recommended OAL, into the lands. I normally do this with a modified piece of brass to barely hold the bullet. Some times I use my comparator, or bolt lift, all depends on the gun. Once I have the Max OAL I can then determine if the bullet I have chose will work with the recommended OAL that the manual suggest. And will it fit the magazine if t has one. In most all cases I start there. Once I have a load that's shooting good then I start changing the OAL to see if I can improve on the group. After that I test with different primers. Once completed I do it all over again with a different powder and/or bullet. There is very seldom a end to combinations.

I load mine as long as possible that will still fit in the magazine and chamber as a starting point. And 95% of the time that is my end point.