COL Newbie question?

[Vettepilot]

Ok, I did a search for this, but didn't really see it covered though I am sure it has been "beat to death" somewhere here...

I am fairly new to cast boolit loading. My question pertains to Cartridge Overall Length regarding various and different cast boolits. Logically, you can interchange loading data with boolits of the same basic design and weight. But what about COL? Obviously, just where the weight resides in a boolit can vary with mold manufacturers as well as the boolit shapes, and thus the actual length must vary.

For just one example, I have some Missouri Bullets cast boolits I have bought, but no actual data for them. So, how do you determine the safe COL for a boolit for which you don't have direct data??

(Presently preparing to load cast boolits for 9mm and 44 mag, though others will follow....)

Thanks in advance for any input!!

Vettepilot

[Walks]

Lots of ways.

1) Adjust seating die/stem to just touch a factory load. Size & expand a dummy case, no powder/primer. Seat one of your cast bullets, no crimp yet. Drop it into the chamber of the bbl of your disassembled pistol. If it plunks, then see if it fits in a magazine. If that works......

2) Check O.A.L. in a cast bullet manual. Compare it to the length of your dummy. If too long seat a smidge deeper.

3) Most of use Factory Loads as a guide when setting up our seat/crimp dies.

4) Just trial & error. Don't over crimp either. Just enough that you can't squeeze the bullet back into the case between your thumb & forefinger.

[toallmy]

With the 44 you can use the crimp grove , but the 9mm is a little more tricky . You need to work out a dummy round that will plunk in the firearms chamber , as well as feed through the magazine - with enough crimp to hold the boollits in place without reducing the diameter of the cast boolits .
What stile boolits are you going to load , and what powders are you going to try ?

[6bg6ga]

Its pretty simple.

1.) Make sure the bullets sets correctly in the barrel with the barrel removed from the gun. The end of the case should be even with the barrel shroud.

2.) The loaded rounds aren't too long to go into the magazine and they don't try to go nose up when ejecting.

I don't pay attention to the OAL lengths listed in the reloading magazines.

3.) I check the tension of my crimp by taking the round and pushing the bullet into the side of my bench. I record the length both before and after I try pushing the round. Any movement or lessening of the OAL means I need more tension.

4.) At the range I set enough rounds out to fill my clip or cylinder. I measure the OAL. I load the clip or cylinder I fire a few rounds dump the clip of cylinder and re-measure the OAL of each round that is left.

[JonB_in_Glencoe]

I moved your thread to a more appropriate section.

For revolver (one gun?), I set the OAL for the gun's throats, then work up a load.

For semi-auto, plunk test for OAL, then work up a load.

[Conditor22]

this is another way,
hold the boolit in the barrel to where it touches the rifling and measure the distance to the end of the barrel (there are many ways to do this use a dowel cut to a certain length and your caliper.
repeat measurement with a case chambered in the gun.
do the math and subtract a couple of thou.

9MM has a tapered case, Don't over crimp and compress/downsize the boolit.
load your first few boolits in empty cases, pull the boolits using a hammer type puller (you can use a shell holder instead of that weird thing in the hammer puller)
measure the pulled boolit and make sure it's not being downsized by the crimp.
adjust the crimp to where it doesn't downsize the boolit.

[mdi]

I have seated revolver bullets to the crimp groove/cannalure and disregarded book OAL since '69. I reloaded for 38 Special then 357 Mag, then 44 Magnum/Special for the first 20 or so years (besides a couple rifle cartridges), then I got a 45 ACP. I used my Lyman Cast Bullet Handbook to determine an OAL for the bullet I used. While some of the 230 RN bullets I used were a bit different shape I continued to use the Lyman data quite successfully and safely, always beginning with starting loads with each bullet change. For my 9mm cast loads I found a similar shape/weight bullet and began with starting loads, and worked up from there to an accurate load. Never any "over pressure" problems...

I never tried the plunk test with any of my revolvers...

[blackthorn]

All of the above, keeping in mind the final position of the bullet base in the case. This is particularly important in cases with limited/small powder space capacity, where seating deeper may raise pressures to above critical levels.

[Larry Gibson]

All of the above, keeping in mind the final position of the bullet base in the case. This is particularly important in cases with limited/small powder space capacity, where seating deeper may raise pressures to above critical levels.

Seating depth, as mention, is critical. That's why, when using a different bullet of even the same weight, you must start low and work up the load in small capacity cases as also mentioned. Never assume a load is safe, even it's with a heavier bullet, if the seating depth is unknown. In small capacity cases such as the 9mm seating depth varies with a given bullet weight because of different bullet shapes. Having pressure tested such in small capacity cases, seating depth can be far more critical than thought.

[JBinMN]

I posted a comment describing how to "extrapolate" to find OAL ( COL) in another topic recently. while others here have described similar methods, perhaps you might find the one I posted helpful as well as the other suggestions here.

It is located here, if you wish to read it:
http://castboolits.gunloads.com/show...=1#post4663349

If you are interested in reading just the part about the "extrapolation" for OAL/COL, look for where I put the "dotted lines', like >> ---------

I am just posting in order to try to help out a bit. Nothing more, nothing less...

G'Luck! in your endeavors!

[fredj338]

Probably the most misunderstood aspect of reloading. OAL is ALWAYS bullet & barrel specific. As noted, for revo, just load to the crimp groove. This works for most bullets in most guns but here the cylinder fit is the important part.
In a semi, things get more complicated. Not only does it need to fit the barrel but also in the mag, all the way down. Some barrels have very short throats & truncated cone or RN with a fat ogive will need to be loaded short.
So what does that mean with regards to data? It means you have to start low & work up. When ever you change a bullet type that shortens the OAL, you have to drop your charge & work it back up. OAL isn't the pressure boogyman many think though. If you never get above target loads, then seating deeper isn't going to cause much of an issue. When working with max loads, everything matters, even the brass case brand you use.

[Vettepilot]

Ok guys, thanks for all the info. I guess the key take away words are: "Disregard the COL as shown in the load data".... I am familiar with loading various distances off the lands, and measuring "Cartridge Base To Ogive" and measuring your chamber to load as such for rifles, and have all those tools. (Actually, I made them myself long ago.) I guess I just didn't realize that a similar procedure goes for loading cast lead boolits for pistol and revolver plinker loads.

I had thought that once you got your barrel and chamber diameter dimensions, and sized your cast boolits accordingly, that you could just load them up to the COL in the load data. My only question was for when your particular cast boolit wasn't shown in the load data, what you should do about COL in that case.

Thanks,
Vettepilot