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-   -   Re-loading and O.A.L. (http://www.firearmstalk.com/forums/f30/re-loading-o-l-101271/)

volunteer0925 12-07-2013 11:47 AM

Re-loading and O.A.L.
 
Hello all.
I am new to the site and have found a lot of good info but nothing on this particular question.
I am fairly new to handgun reloading and I am loading for my Sig 226 40 S&W and am already finding great advantages to reloading other than the obvious of money saving and availability, but at the range also.

I have been reading numerous books and manuals on the subject, one of them being "Reloading for Handgunners" by Patrick Sweeney.
In the section talking specifically about 40sw he describes a process of taking a dummy round of almost 10mm length and with the recoil spring removed from the pistol, cycling the round through and the resultant OAL of the ejected round is "the length for your gun" He also describes how to find the max OAL of your pistols chamber by first measuring the OAL of the separate bullet, dropping it into the the removed barrel, measure from the hood of the barrel to the base of the bullet. Add the length of that distance to the OAL of the bullet and that is the maximum "loaded" OAL of that particular pistol.
So I did all that. With a resized case of .843, and new bullet @.532 the measured depth was .721+bullet@.532= 1.253. I cycled a dummy round from the magazine, into the chamber and ejected it with a round of 1.207.

So I am not sure what this actually tells me?
Am I to assume that the longer OAL of the reloaded round will be more accurate given that if I were to back off the length a few thousands from the new length that the bullet has less distance to travel than a spec. OAL of 1.125 before it hits the rifling? The other effects being that there is more dead space in the shell, less brass to bullet contact, is he saying that I can load a heavier wt. bullet and keep the same grain weight of powder?
He ends the section saying that when crafting ammunition for your "competition" pistol the "correct" OAL of .40 ammo is what it is, there is no common or average length.Is this a common or even a safe process?
Thanks for any info or response's.

duddie10 12-07-2013 12:10 PM

First off welcome i hope you enjoy ur stay at ftf. With reloading as you can see every one has there different ways of doing thing. What he is talking about is each barrel is different. Even tho there such tight tolerances when maching there all different. Measuring your chamber is a good place to start. I would look into doing a chamber cast. Its real easy and not only can you measure exactly what your chamber length is, you can also see any problems with it or the rifling. Another good thing to do is cross reference between well known reloading manuals. To get to your question. Ive always juat used what col from the books i have. It can be dangerous if you dont have the bullet seated right. It changes the chamber pressures. For .40 sw with a 155 grain hollow point the col.is 1.120 thats out of my speers book. From hornady its 1.125. From hodgdon reloading its 1.125 Now the max col is 1.135. Id start there if your using a 155gr hp. Hope this is helpful

gr8oldguy 12-07-2013 12:18 PM

First off welcome from Wisconsin. I'm not sure about the process you described. When I'm setting OAL I use my lee reloading book as a guideline and the chamber of the gun I'm reloading for as the standard. I use what some call the kerplunk test. Once the round will fall effortlessly into the chamber with a distinctive "kerplunk" sound and fall out easily with no help from me the round length is set. Then I measure the length and compare to my book. They are rarely the same. I've found that published lengths seem to be longer than what will fit my guns. What I've found is bullet design will have an effect on OAL. For example, I bought some hard cast 115 Gr bullets to use in my CZ 75B. The bullet ogive was too full and caused the OAL to be too short for my comfort level. So I found a bullet design in a 125 Gr Lee mold that is perfect. I used the other bullet for cowboy loads in my ruger blackhawk. All this being said, OAL is a big aspect of loading safe, accurate rounds. Too long and pressures might not be as high as needed for a good solid round. Too short and the potential of creating a dangerous situation is a reality. I always handoad light loads. I like reduced recoil. That's just me. I'm old and so are my hands. Good luck.

Rick1967 12-07-2013 12:36 PM

While I have never heard of someone doing this with a handgun...people do it with rifles all the time. Often people will experiment by having the bullet as close to the lands as possible without touching. But people shoot rifles for precision. They often try to squeeze 3 bullets through one hole at 100 yards. You don't do that with factory ammo. That is when this type of thing comes into play.

You don't want it so long that it is going to force a bullet into the rifling. And I would not do this with hot loads. Sometimes when firing heavy loads, rounds in the mag can be affected. The last round in the mag could end up longer than the others. It is because as the gun is fired the rounds in the mag can "jump crimp". They will back out of the case ever so slightly under recoil. When you have a few thousandths to spare its not a big deal. When you are already 1 thousandth off the lands...now you many not go into battery. Or you may jam a bullet in the barrel.

mseric 12-07-2013 01:31 PM

Here is how I find the Max OAL for all my handguns. Letting the action slam the round home may give false readings.

http://i2.photobucket.com/albums/y17...ibilitiesx.jpg

volunteer0925 12-08-2013 12:52 PM

Duddie Thanks,
I am slowly building up my library and reading different manuals for that exact reason. How does one go about getting the chamber cast and who would you suggest doing that?

volunteer0925 12-08-2013 01:01 PM

Thanks gr8oldguy (old guys rule)

As of now I will not be trying the process outlined, but I am always up for tying something new (and safe) that will improve my accuracy. It sounds interesting, but I don't feel confident in my reloading experience yet to "experiment" outside of the expected powder / bullet / primer combinations and load practice.

volunteer0925 12-08-2013 01:11 PM

Rick,
So the practice is in fact to improve accuracy then. I had read a similar article somewhere else but cant remember where, but the author suggested backing off the distance to the lands a few thousandths also. The problem I see with my experience is judging how much is a safe minimum brass-bullet contact surface and what kind of charge is safe since now I'm off the radar with data specs.
Like your Jeep. Ive got a 2001 Wrangler, love it!

volunteer0925 12-08-2013 01:24 PM

Mseric thanks for the diagram.
I went back and looked at what I have and compared it to your diagram and even at 1.207 OAL the brass is still maybe .010 shy of the butt of the barrel. But what I did find after paying closer attention to what I was doing, was even though I loaded it in the magazine first and racked the slide etc... when I attempted to push it fully into the mag again (as if I were loading more rounds) I realized it will not fit (too long). Hm, so how do other shooters get around that issue? I only imagine that not all pistols have as deep a chamber as the sig226 (seems deep) and going longer than the Spec. OAL to almost reach the rifling isn't extending the round much at all?

Rick1967 12-08-2013 02:08 PM

That mag is the deciding point on many guns. My 1911 mags are pretty shallow. And they are all the same for 1911 guns. They are all interchangeable. But I had a Ruger P90 that is a 45. It had much deeper mags. I know because I was loading much longer for that gun. But the rounds I made for that one would not fit in the mags when I bought my first 1911. That is when I stopped using my semi-wadcutters.


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