COL for different 124gr 9mm bullets

[Lugnut]

I used a 1.15" COL for several hundred rounds of 124gr Winchester bullets- with 6.0gr Power Pistol. These rounds fired just fine in all my guns. The 6.0gr PP was well below the max according to Alliant's web and the Speer book.

Now I'm using 124 gr Berrys plated bullets. I noticed that the Berry bullets are .020" shorter. Sooo should I decrease the COL to 1.13 or so? To get more brass around the bullet? I've got the LNL ready to go!

 

[GTOShootr]

If it works, I'd stick with the reliable length you found. If you do shorten, you'll be increasing the pressure, so you might want to back off on the charge if you want to maintain the same feel. It is one of those things where having a chrono is nice.

 

[Lugnut]

If it works, I'd stick with the reliable length you found. If you do shorten, you'll be increasing the pressure, so you might want to back off on the charge if you want to maintain the same feel. It is one of those things where having a chrono is nice.

Yeah I wish I had one. However.. the reason I want to shorten them is to get the SAME pressure. Since the Berrys are shorter, when I keep the same COL I get more volume not less... I want to shorten the COL to keep the same volume.

 

[Finalygotabeltfed]

If you are switching from jacketed to plated bullets your pressure may vary anyway due to resistance in the bore. Experiment and find what works. I doubt you'll blow up your gun with a .020 difference in length. Load a few and see how they feed and shoot. If they work, all is well, if they don't feed or shoot erratically, you pull a few bullets and adjust the length...no big deal. Your gun might not like plated bullets at all and may not feed no matter what length you make them.
Sounds like you have some room to work with your load....go for it.

 

[Lugnut]

My gun BETTER LIKE them! I have a few thousand plated bullets. LOL.

I know I should make small batches and test them... I'm sad though. I was going to make several hundred tonight.

 

[EddieCoyle]

Lugnut,

Unless you make them way shorter, the pressure will not go up. For the same bullet weights, plated bullets have a lower pressure than jacketed. You can load them to either 0.020" shorter, or to the same OAL as the jacketed bullets - either way, the pressure will be lower than before (the velocity will likely be higher though).

 

[GTOShootr]

Yeah I wish I had one. However.. the reason I want to shorten them is to get the SAME pressure. Since the Berrys are shorter, when I keep the same COL I get more volume not less... I want to shorten the COL to keep the same volume.

I misunderstood you since you said to "get more brass around the bullet". Messing with OAL is not the way to adjust your load to increase power, especially when it works. Adjust the powder, if you even notice a difference. No reason to abort your reloading session. I switched between plated and jacketed with .40 a couple times, and even with chrono requirements to meet for PF goal, never had to change the charge more than a couple tenths.

 

[Lugnut]

Just to post some closure on this.

I snuck to the range this morning to test some rounds before the "big production".

I found no discernable effects at all with the Berrys bullets in either: 1.120, 1.130 and 1.150 COL. All loaded with 6.0gr Power Pistol. I didn't have a chrono but the cases all looked fine, the felt recoil was the same and accuracy didn't change. Gun (Sig 228) cycled with all rounds just fine.

Sooo... I think I'll crank some out at 1.130" COL (which gives me the same powder/bullet gap in the case as I had with the Win FMJ bullets).

 

[EddieCoyle]

Just to post some closure on this.

I snuck to the range this morning to test some rounds before the "big production".

I found no discernable effects at all with the Berrys bullets in either: 1.120, 1.130 and 1.150 COL. All loaded with 6.0gr Power Pistol. I didn't have a chrono but the cases all looked fine, the felt recoil was the same and accuracy didn't change. Gun (Sig 228) cycled with all rounds just fine.

Sooo... I think I'll crank some out at 1.130" COL (which gives me the same powder/bullet gap in the case as I had with the Win FMJ bullets).

Good choice. Just for the record, I found that the Berrys 230gr .45 bullets were also 0.020" shorter than the jacketed bullets I had been using. I loaded those to 1.250" (I had been loading the jacketed ones to 1.270") and they shot just fine.

 

[Lugnut]

Good choice. Just for the record, I found that the Berrys 230gr .45 bullets were also 0.020" shorter than the jacketed bullets I had been using. I loaded those to 1.250" (I had been loading the jacketed ones to 1.270") and they shot just fine.

Thanks. The funny thing is I have just finished 1000+ rounds of .45 as well. I had some Speer 230gr FMJ bullets and loaded to a COL of 1.265" but I didn't notice the difference with the Berrys 230gr bullets and kept it at 1.265"!!!! I'm not too worried but I might adjust my next batch of Berrys.

 

[EddieCoyle]

Thanks. The funny thing is I have just finished 1000+ rounds of .45 as well. I had some Speer 230gr FMJ bullets and loaded to a COL of 1.265" but I didn't notice the difference with the Berrys 230gr bullets and kept it at 1.265"!!!! I'm not too worried but I might adjust my next batch of Berrys.

It probably doesn't matter much either way. For most cartridges (unless you're really trying to push the envelope) there's enough of a safety factor to allow for minor variations in bullet shape and length without putting you in danger.

For example, on hand right now I have 4 different 180 gr RNFP FMJ .40 caliber bullets from 4 different manufacturers for loading 10mm. These bullets have slightly different lengths and shapes. When I load them, I'll do my best to keep the volume under the bullet the same when I change bullet types. As a result, I'll end up with different a C.O.A.L. for each bullet.

If I find that one or more of my guns has a length induced reliability problem, then I'll cross that particular bullet and load off of my list. Fortunately, I own revolvers in most of my auto calibers so these bullets seldom go to waste.

There are some calibers, like the .40 S&W where you need to be more careful with the case volume. I don't own a .40 S&W, but if I did and if I loaded for it, I'd be very careful about the C.O.A.L. I'd probably end up having to buy bullets retail instead of the usual eBay-bullet-of-the-month club.

The one caliber where I've started to push the envelope is the .460 S&W Magnum. For this, I use the exact bullet (weight,shape, and manufacturer's model number) indicated in the load data, and I load to the exact C.O.A.L. recommended.

In this case, the bullet itself is pretty important. Because they both use .452" diameter bullets, it is possible to load a jacketed bullet meant for the .45 LC into a .460 case. The problem is that a bullet intended for a .45 Colt might disintegrate when you try to drive it up over 2000 fps, and that would be bad.

 

[Lugnut]

Good information. Thanks. I do have .40S&W reloading dies but I haven't done much with reloading them yet... that will probably change after I finish a good sizable batch of 9mms.

 

[TonyD]

Just my opinion, and you can take it for what it cost you.

Find a COAL that reliably feeds in your gun for the bullet type you're using and stick with it - regardless if one is .020 shorter or not. Adjust your powder charge to effect the desired velocity.