" Over All Length Of Bullet"

[runangun]

How do you know what oal to use on each gun you use? Is there some place its written that you can only use certain oal lengths with certain guns? And how does that play into how much power and what type of power to use?

PLEASE EDUCATE ME SO I'LL BE AS SMART AS YOU GUYS.

Thanks in advance for your help.

[PistolJim]

Wow-

Eric said-

People who load "long" hopefully have barrels modified (freebored) to avoid pressure problems that might occur if the bullet were to be too close to the rifling.

I've never heard that before. I have a stock Para P16-40 and I've had a few casehead seperations using 200gn. bullets (1.200 oal). If I used Star bullets the slide would go into battery but I tried Zeros once and they have a slightly different shape and the bullet would hit the rifling causing the gun not to go into battery but it would still fire. I caught on to the slide being out of battery before I shot 50 rounds and the Zero's never caused a case head seperation. Only the Stars. I loaded both at 1.200 oal.

I switched to Star 180's even though I prefer the feel of Star 200's in my muzzle lite Para. I still load at 1.200 oal. but with the 180's I haven't had a problem. Now I wonder if I should try the 200's again with a shorter oal.?

Eric how much clearence between the rifling and the bullet (contact) do you think is correct?

Sorry for the drift.

Jim A44594

[Guest Larry Cazes]

You would normally consult a powder or bullet manufacturers data book and load to their suggested OAL using their suggested powders for the bullet weight you choose. The published dimensions are based on SAAMI (Sporting Arms and Ammunition Manufacturers' Institute) specifications for the caliber you are loading which all gun manufacturers follow and if you use this data you should be safe. Assuming that you are going to load to a longer OAL then your load data book shows, you need to use your own judgment and experience and should be absolutely sure of what you are doing before you proceed. Again remember that you are now loading outside of any published load data and should use extreme caution.

I make a judgment of OAL (overall length of the loaded round) based on the length of the magazine front to back and also take into account the chamber of the gun that the load is being developed for. My SV mags will fit my bullets loaded out to as much as 1.240 but function well if loaded to at least 1.180. I chose 1.20 as a compromise between the two. With the bullets you intend to use, load up a few rounds and use your chamber as a case gauge. Remove the barrel from your gun and insert the loaded round into the chamber and check to see if it drops in without any interference from the rifleing or throat of the barrel. The base of the case should be flush or below the level of the barrel hood. You should also be sure that there is enough of the bullet seated into the case so that you get sufficient case neck tension. Again using a finished round place the bullet against a flat surface and try to push it into the case. It should not move easily. This is important because if there is not sufficient neck tension, the bullet may be pushed deeper into the case when it is loaded during the firing cycle. This is generally referred to as bullet setback and is a bad thing. This could lead to dangerous rises in chamber pressure. I now proceed to do normal load development using a chronograph to ensure that pressures are below the published maximum set by SAAMI in the load data book for that chambering, powder, and bullet weight.

Larry

[George]

Here is a page with data for a few common pistol calibers. Do not exceed any specified Max OAL unless you are sure of what you are doing. You are generally better off staying within established Max/Min for each caliber. There are few if any advantages to be had in loading beyond Max OAL with pistol cartridges.

http://www.rainierballistics.com/loaddataAA.htm

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Regards,

[ErikW]

Jim, you'll have to ask a gunsmith. The way I understand it, you need some "free bore" ahead of the bullet in which it "jumps" to the rifling. Without enough jump, pressure goes too high too soon. Merely not touching the rifling may not be enough jump. Freeboring a barrel is a $10 modification.

Why load .40S&W long?

Because the 1911 platform was designed around a 1.25" cartridge. The .40S&W was designed to fit 9mm size guns and is only a 1.13" cartridge. When you try to feed it through a 1911/2011, it might not feed. So, you lengthen it to around 1.200".

Why not load .40S&W long?

See above about getting too close to the rifling. <Kaboom!>

Assuming the freebore situation is OK, now the major problem is the load data for a 1.13" cartridge is nearly worthless with such an increased OAL. The bottom of the bullet is so much farther away, there's so much more case capacity, pressure decreases and velocity drops. Now you need more powder to get the velocity up, so much more powder that you may be well above the maximum charge in your loading manual. <shrug> Now what?

There are also reasons for loading 9mm long... Feeding in the long-geometry guns, decreasing pressure, and increasing powder to work a compensator.

Then there are the reasons for loading rifle long... <sigh> Let's not go there.

I agree with George, stick to published lengths until you've been reloading a while and you encounter a situation that requires you to load long.

Edited January 9, 2004 by Erik Warren

[runangun]

With the information you guys provided so far, I'm going back to the gunsmith who built my STI and ask him why he's telling me to load at 1.185 oal.

[Patrick Sweeney]

There's an easier way to determine absolute max oal (amoal). Use dial calipers to measure your barrel length from hood to muzzle. (Obviousl disassemble it.)

For the bullet measuring I turned a set of stands out of aluminum. Each stand is as long as a standatd loaded round, and a cylinder smaller than the chamber it is to work in. I place a bullet on the stand and gently push the chamber end of the barrel down over it. When it stops, I use the dial calipers to measure inside the bore from the muzzle down to the bullet nose. Subtract the internal measurement from the external, and you have your amoal.

The amoal for a barrel will differ for every bullet design. A point-nose bullet will have a much longer amoal than a flatpoint would.

The bullet stops when it reaches an internal diameter small enough to act as a shoulder. Often, the amoal is a lot longer than the absolute maximum magazine space. But it does tell me how much I have to work with, and alert me to a short, steep leade off the chamber.

[Gun Geek]

Patrick:

I like you approach, but I don't have access to metal working equipment.

I use a product called cerrosafe (Brownells and Midway have it). This suff is a metal alloy with a very low melting point (less than the boiling point of water). I make FULL LENGTH chamber casts of all my rifles and pistols. By full length, I mean that it action is locked so that the cerrosafe can fill the entire cavity from the breach face to about 1/2" of rifling.

The cool thing is that I get an exact copy of my chamber so that I can directly measure things like headspace, freebore, etc. I can also watch to see if there is any throat erosion (more of a rifle issue)

Things to be careful of -

1) Be sure you remove things like the extractor so that it doesn't get embedded in the cerrosafe.

2) Coat the surfaces with a little fresh oil - works a release agent.

3) Plug holes (ie. firing pin, unsupported ramp areas.

If the cerrosafe runs into places you don't want, don't panic. If flakes off really easy.

I keep the castings and make new ones at certian intervals, so I can see how things are changing. I haven't noticed any real change in pistol chambers, but I have in rifles.

Geek

[George]

I use an even simpler method. I load a bullet too long in an empty, unprimed case, paint the bullet completely with sharpie and let it dry. Then I carefully drop it into a clean chamber and close the slide with the extractor removed and if it sticks, I keep seating one a tad deeper until it doesn't, if it doesn't stick I keep seating one a little longer until it comes out with a disturbance to the sharpie coloring on the bullet. It isn't micrometer accurate, but it gets the data for you. I have always found this measured Max OAL to be a bit longer than the recommended Max for the cartridge, so there is some tolerance to be had here. BTW, this will be a different measurement with every new bullet profile. This is not one size fits all.

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Regards,

[Guest Larry Cazes]

Patrick and Geek, I'd be interested in seeing the data you've measured for your barrels. Years ago, All of the large rifle manufacturers started cutting all of their rifle chambers with large amounts of freebore to minimise their liability from handloaders. Most people who load rifle calibers to optimise accuracy will seat their bullets out to either touch the rifleing or come within .005 and in any of the commercial rifles I've measured you cant come anywhere close. I have a tool for rifle chambers which allows me to measure the lead to the rifling which actually uses the bullet desired and a fired case. I'd be interested to see if pistol barrel makers are leaving a very long lead as well.

Larry

[TBF]

Runangun,

My method for autopistol OAL is not nearly as technical as some of the above.

But it works for me.

Using the bullet you want to load ( different bullets have different profiles and different OAL's ) . Make up some dummy rounds, 3-4 is enough, make them long as the mag will allow, and still allow free movement of the stack of bullets. Load 1 round .020" longer than will work through mag.

Drop one into your barrel ( unassembled ) , if it fits ( usually does ) drop in the +.020 round, it will probably fit too. Job finished.

In most pistols this is all you need to do to find the max OAL. 1911's shooting 9mm and custom barrels, or mags for another cartridge will obviously be different.

Finding the OAL that feeds and functions perfectly is a matter of working backwards from max OAL. Use caution as you shorten the OAL,pressure climbs, sometimes not in a linear fashion. Use start load from tested data and NEVER load shorter than MIN. OAL.

Good advice above too, but this is the quick and dirty method.

Travis F.