9mm C.O.L.

[hdwhit]

I am getting ready to start working up a 9mm Luger load using HP-38 with some 115 grain bulk bullets that I bought some time ago. The bullets look like Hornady XTP bullets except that the transition from the body of the bullet to the ogive is not quite as abrupt as on the Hornady. The bullets are 0.355 in diameter and 0.547 in length.

For reference, the Hornady XTP is 0.355 diameter and 0.545 length.

I will be starting at 3.7 grains as I know from prior experience with similar bullets that the 3.5 grains recommended in Lyman #49 will not reliably cycle my pistol. 3.7 grains is still less than the starting load listed in Hornady #8, Speer #11 or Hodgdon's web site, so I believe that is reasonable.

I also know from prior experience with similar bullets that above 4.7 grains, I start to get pressure signs, so I will regard 4.7 grains and not the 4.9 grains given in Lyman #49 as the maximum loading. As the spread between minimum and maximum charge is 1.0 grain, I plan to select 0.1 grain as my increment.

My question has to do with C.O.L.

• Hornady #8 says 1.075 with their 115 grain XTP. As my bulk bullet is 0.002 longer, this would suggest a length of 1.077 to keep cartridge volume the same.
  
• Lyman #49 gives a c.o.l. of 1.090 with an unidentified Jacketed Hollow point.
  
• Speer #11 doesn't recommend a c.o.l. for their 115 grain bullets, but does say 1.080 for the 100 grain and 1.100 for their 124 grain bullets. Interpolating between these two figures gives 1.093
  
• Hodgdon's website gives a c.o.l. of 1.125

So, with this kind of variability, where should I start?

1. Should I be conservative and start with 1.125 and see how it does?
2. Or go for the more-or-less consensus of 1.090-1.093 from Lyman and Speer?
3. Use 1.077 because of the similarities of the bulk bullet to the Hornady XTP?
4. Or something else entirely?

I will have a press available at the range, so I could seat everything out to 1.125 and if the first few rounds don't work for some reason, shorten the c.o.l. by a few thousandths and try again.

With 0.1 grain increments between 3.7 and 4.7 grain, I'm already committing 110 bullets from my bulk purchase just to load the various strings for load development and I don't want to spend a bunch more having to chase my tail over c.o.l. if I can get it nailed down a little better.

Thanks.

 

[Walkalong]

A picture would help, but I would lean towards 1.080(+/-) to start.

Another thought. Seat them with your seater set as it is now for your similar 115 Gr bullet (Assuming JHP) and see what it comes out at. Should feed well that way.

 

[hdwhit]

Walkalong wrote:
A picture would help,

A picture of what? The two different bullets?

 

[hdwhit]

Walkalong said pictures might help.

I assume he meant pictures of the bullets. On that assumption, I have attached copies of side, top and length views of the two bullets. The Hornady XTP is the one on the left in the side and top shots and is the one 0.545 long.

 

[Walkalong]

The XTP has more full diameter shank and can be seated deeper. I don't know how much of that full diameter shank is out of the case at factory OAL though.

Not long ago I bought some 124 Gr JHPs from RMR (Not the new in house ones) and they look similar to the bullet on the right and measured from .557 to .560 long. I loaded them at 1.120 to 1.125 and they have functioned well. I worked up to max with N340 and got 1110 FPS from a 3" EMP, 1234 FPS from a 5" S&W 1911, and 1307 FPS from a 16" AR. You won't get that with the slower, but good, W-231.

 

[noylj]

There is no COL that is best for any cartridge, any bullet—it depends on the gun.
As described below, first find the COL that fits the magazine and feeds and chambers in your gun and then start load testing from the start load on up.

Per Ramshot:

"SPECIAL NOTE ON CARTRIDGE OVERALL LENGTH “COL”

It is important to note that the SAAMI “COL” values are for the firearms and ammunition manufacturers industry and must be seen as a guideline only.

The individual reloader is free to adjust this dimension to suit their particular firearm-component-weapon combination.

This parameter is determined by various dimensions such as

1) magazine length (space),

2) freebore-lead dimensions of the barrel,

3) ogive or profile of the projectile and

4) position of cannelure or crimp groove.

• Always begin loading at the minimum ‘Start Load.’"


Your COL (Cartridge Overall Length) is determined by your barrel (chamber and throat dimensions) and your gun (feed ramp) and your magazine (COL that fits magazine and when the magazine lips release the round for feeding) and the PARTICULAR bullet you are using. What worked in a pressure barrel or the lab's gun or in my gun has very little to do with what will work best in your gun.

Take the barrel out of the gun. Create two inert dummy rounds (no powder or primer) at max COL and remove enough case mouth flare for rounds to chamber (you can achieve this by using a sized case—expand-and-flare it, and remove the flare just until the case "plunks" in the barrel).

Drop the inert rounds in and decrease the COL until they chamber completely. This will be your "max" effective COL. I prefer to have the case head flush with the barrel hood (or a few mils higher than where the head of an empty case aligns with the barrel, as all cases are too short and I prefer to minimize head space). After this, place the inert rounds in the magazine and be sure they fit the magazine and feed and chamber.

You can also do this for any chambering problems you have. Remove the barrel and drop rounds in until you find one that won't chamber. Take that round and "paint" the bullet and case black with Magic Marker or other marker. Drop this round in the barrel and rotate it back-and-forth.

Remove and inspect the round:

1) Scratches on bullet--COL is too long

2) Scratches on edge of the case mouth--insufficient crimp

3) Scratches just below the case mouth--too much crimp, you're crushing the case

4) Scratches on case at base of bullet--bullet seated crooked due to insufficient case expansion (not case mouth flare) or improper seating stem fit

5) Scratches on case just above extractor groove--case bulge not removed during sizing. May need a bulge buster.

 

[Walkalong]

There is no COL that is best for any cartridge, any bullet—it depends on the gun.

This is most certainly true for accuracy, although just like rifles you can find one that works very well in many weapons. Function is another thing entirely, and ammo makers have to find an OAL that will work in all SAMMI correct chambers.

As described below,

The "Plunk" test.


There are OALs for any one caliber/bullet that work in the vast majority of guns, or ammo makers would be in a bad state of affairs. Optimizing OAL for your gun is another thing entirely, and what handloaders often do, realizing it may not work in another weapon. I tend to find an OAL that feeds 100% and will fit everything I have rather than optimize it for one pistol, but then I am not shooting bullseye, nor can I hold as well as the ammo shoots.

 

[ArchAngelCD]

Here's what I do, it may work for you too.

I usually load my semi-auto ammo as long as possible within SAAMI limits and still pass the Plunk Test. Like said above, let your gun dictate the OAL of your ammo.

 

[Rock185]

Hello hdwhit, some of the guys have given excellent advice. Having reloaded mega thousands of 9MM since the '60s, I'll contribute .02 worth too. I've achieved best reliability with this cartridge by loading to the longest overall length consistent with reliability. The longer length allows the cartridge to breakover from feed ramp to chamber at a less abrupt angle. The XTP, and similar bullets with a truncated cone type ogive, make OAL more critical in my guns because the full diameter portion of this type of bullet will run into the chamber leade in some guns before the cartridge is fully seated. This is not so much of an issue with projectiles with a longer, more rounded, ogive, whether JHP or round nose,etc. No matter what the manual says, I use barrels out of my particular guns as chamber gauges, make up dummy reloads, do "plunk" tests to confirm the round will fully chamber in my particular barrels, check that the bullet ogive does not interfere with the rifling leade, check that taper crimp is correct,etc. Finally, I make up a small quantity to actually test at the range for functional reliability, velocity, pressure signs,etc. prior to loading in quantity..........ymmv

 

[DeadEye9]

A picture would help, but I would lean towards 1.080(+/-) to start.

Another thought. Seat them with your seater set as it is now for your similar 115 Gr bullet (Assuming JHP) and see what it comes out at. Should feed well that way.

I have loaded and shot 1000s of actual Hornady XTP 115gr for weekly action pistols shoots and HP-38 was my go to with that load for a long time. I wasn't competing with anyone but myself, so there were no power factor issues and I basically loaded for what I shot the fastest most accurately. Eventually (and currently) I switched to the 124 XTP and Power Pistol for my 9mm accuracy loads, but with the 115 and HP38 I had good results @ 1.080" and 4.1gr. This was a "powder puff" load out of my Glock 17/19 pistols and still very tame in small single stacks like my M&P Shield, but it functioned perfectly in all of my firearms with minimal recoil and good accuracy. Another benefit was that it's economical as a single lb of HP-38 will loads a few thousand rounds of that load. For reference I use CCI small pistol primers for my 9mm loads and brass is typically CBC/FC/WIN/Speer head stamps, with the occasional batch of Aguilla or Starline when I build up a good lot of it to load.
Best of luck.

 

[mdi]

K.I.S.S.! The bullets you have (who made them?) are very close to Hornady bullets so just use Hornady load data and OAL for the 115 XTP bullets. I have some RMR JHP bullets that are close to Hornady bullets and I've successfully/safely used Hornady data for a few hundred loads. Two thousandths of an inch is negligible, and don't overthink this, it'll make you crazy worrying about .002"...