Pistol OAL for bullets.....

[Nevada Ed]

There are always questions on what is the correct OAL for a bullet or
if the Data that is being read, is correct for what the person is using.

I just want to start with.........
if your bullet has a "Cannelure Band" on it, 99% of the time this can be the correct OAL for this bullet.

The next thing that I look for is the type of tip or Ogive that the bullet has.
There are Round nose, Flat Nose, Hollow Points and even some look like a Phillips screw driver.

Most of the lighter weigh bullets do not cause a problem in a 9mm case but when you get up in the 147 gr. bullet weight class or heavier, the length of the bullet and the style of it's tip, can be very important in the OAL that you set it at.

For example;
Take the Speer 147 TMJ with a small flat tip and the Berry 147 gr. plated Round Nose bullet.
They both weigh 147 grs but the length of each bullet is very different and the seating depth into the 9mm case not only changes the amount of powder that it will accept but also the pressures of the load per case volume at hand.

The 9mm case, being a tapered case, will also build up pressures as a bullet is seated into it's depths. In the cast of the long Berry 147 RN bullet, it can bottom out and be tight against the brass case before it reaches a seating depth of .30"

Deeper seating will start to deform the case and could cause super high pressures for the shooter.

This will happen in any pistol load, be it 380 or 10mm.

Here is a picture that I have in my loading notes, that might help other loaders understand what is happening as a bullet is being seated and why the OAL in manuals is important, to control pressures and produce safe loads.

Stay safe.

 

[stansdds]

Reloading 147 grain bullets in the 9x19 has always been a seating depth challenge. There simply is not a whole lot of case capacity. The solid bullets are not too bad, but when you start using hollow point bullets... the lead displaced by the hollow cavity has to go somewhere and the only available place is in the base of the bullet. Some hollow point 147 grain bullets even feature a boat tail design due to the lack of case volume and that will help with bulged brass issue.

 

[Rogeronimo]

Remington has a solution incorporating a curious 'bump' on the base of the bullet ... works great.

 

[flyrobb]

Remington has a solution incorporating a curious 'bump' on the base of the bullet ... works great.

I'm assuming this is a manufacturing defect? If not I'm stumped as to the purpose.

Regarding COL. Does anyone use the length of the bullet to adjust the COL? If you take the difference in bullet length and adjust the COL to give you the same amount of case space wouldn't you get more consistent rounds and pressures? Now I'm referring to bullets of similar types and weights, for example 115 grn RN from different Mfg. that vary in length.

Any validity to my thought process?

 

[Rogeronimo]

I'm assuming this is a manufacturing defect? If not I'm stumped as to the purpose.

Not a defect, but as previously mentioned, the bump doesn't contact the sidewall, allowing the shortest possible C.O.A.L. without bulging the case. A bump instead of a boat tail.

 

[Rogeronimo]

Regarding COL. Does anyone use the length of the bullet to adjust the COL? If you take the difference in bullet length and adjust the COL to give you the same amount of case space wouldn't you get more consistent rounds and pressures? Now I'm referring to bullets of similar types and weights, for example 115 grn RN from different Mfg. that vary in length.

Any validity to my thought process?

Of course there is. Referencing Ed's cutaway, if we consistently only seat .30" of projectile into the case, the boiler room square footage will be uniformly preserved ... only the C.O.A.L. will vary when we change bullet length. Point is, with the big 147's, don't cheat the case to pass your plunk test, or resolve any feed/magazine issues.

 

[Nevada Ed]

If we had ALL the correct lengths for a bullets OAL, everything would be beautiful but it............ AIN'T.

Many of the parties that put out loading data, only list the maximum 9mm OAL of 1.165".
This does little for the JHP bullet loaders, mostly if only using 90 grains !!

There are also manuals with just the shortest OAL of 1.050 for a 115gr bullet.

One reason you need to reed between the lines and find out what OAL will be SAFE in your pistols and also give you some accuracy.

Stay safe.

 

[STORMINORMAN]

A bullet with a traditional round (or conical, if you prefer?) point will certainly be seated deeper in the case than a bullet with a flat point, all other things being equal (.i.e., bullet weight, hollow-point, hollowed base, etc.) if loaded to the same OAL. There will be more of the bullet base further into the case. Look at a true ROUND NOSE (Berrys 100gr RNFB) vs. the approximate same 100gr bullet from Xtreme (with a small flat nose) and a 100gr FMJ (Hornady) sitting on a flat surface: their heights will differ.

The OAL for 147gr 9mm (and for 357 SIG!) really does require some thoughtful analysis. You can change the available case volume dramatically, increasing pressure and performance, sometimes disastrously so! Bullet design in semiautomatic pistol calibers (when used in semiautomatic pistols) does make a difference: in revolvers, not so much.