C.O.L question

tinymike66

tinymike66

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Hiya.
So I have 45 acp 230gr plated RN.
I figured out the charge.
But the COL varies on Hodgdon site and my Lymann 49th edition
Im using 4.3gr titegroup
Hodgdon says 1.200" col
Lymann says 1.275"

H data is for FP
L data for RN TMJ

What ya think?
 
tinymike66 said:
Hiya.
So I have 45 acp 230gr plated RN.
I figured out the charge.
But the COL varies on Hodgdon site and my Lymann 49th edition
Im using 4.3gr titegroup
Hodgdon says 1.200" col
Lymann says 1.275"

H data is for FP
L data for RN TMJ

What ya think?
Click to expand...

I reload thousands of 45 with titegroup and 230 gr rn. I've found that my 1911s like the longer end in terms of feeding so that's what I stick with. It also works fine in my HK 45 .
 
I'm not at home to tell you exactly how long my rounds are but I think if you start at 1.240 , make 5 rds and increase by .005 and make some more. Try them and see what you gun likes
 
Last edited:
PitBull1973 said:
I'm not at home to tell you exactly how long my rounds are but I think if you start at 1.40 , make 5 rds and increase by .005 and make some more. Try them and see what you gun likes
Click to expand...

1.40? wow that's Long.
I'm gonna do the suggested 1.275 and drop it in the barrel and check it that way.
lot of good info though.

thank you everyone!
 
COL/OAL is different from barrel to barrel. you should do a barrel drop-in test to determine the best for you. as for how to do it, read the sticky on this forum or on internet. there are plenty.

tinymike66 said:
Lol..whew. Was gonna say.
That sounds reasonable
Click to expand...
 
I have Hornady 115 gn bullets for a CZ SP-01. Hornady manuals says COL of 1.100". I dropped a test bullet and brass and came up with 1.112". Too far? Other question I have is, do I have to change the guide rod spring?
 
Knotking, since you're mentioning 115gr bullets, I'm going to assume your SP-01 is in 9mm Luger? The SAAMI specifications for that calls for an OAL of 1.000" to 1.169", so your firearm should be able to accept everything that's within that range. Your dropped bullet is at 1.112", so it's not too long. I've been loading at 1.117"-1.123" lately, and sometimes closer to 1.150" when approaching max powder charges to minimise the peak pressure on firing.

What length is optimal or not for your barrel would depend on the shape of the projectile (ogive) you're using and the length of the leade (freebore) in your barrel, as far as I understand the concepts.

I've been trying to perform the drop-in test on the chamber of my 9mm Cx4 without success... even when setting a bullet to be way overlong (nearly 2"!), the projectile wasn't getting pushed into the case and the whole thing extracted easily, no pulling force required. I'm considering getting some kind of non-sticky putty and shoving it in there to get a negative of the chamber, leade and rifling start. :)
 
As long as the dummy round move freely in the barrel, the bullet shoulder not touching the barrel and it load/unload/eject fine from your mags, you are fine.

knotking said:
I have Hornady 115 gn bullets for a CZ SP-01. Hornady manuals says COL of 1.100". I dropped a test bullet and brass and came up with 1.112". Too far? Other question I have is, do I have to change the guide rod spring?
Click to expand...
 
Grawfr, yes it's a 9mm Luger. You're right, I should've been more specific. I've been scratching my head on trying to get it right straightaway. I put the weapon back together and the test round cycled from the magazine and out with no problem, and withdrew from the lone barrel without issue. It was slightly more than 1.112 but I backed it off by a bit (forgot how much) according to the guide referenced earlier.

That's not a bad idea, getting a negative of the barrel.

Any information on the guide rod spring? Can I continue to use the factory spring? I only plan on doing a few rounds to see how it performs. Unrtunately, I only have a box of 99 left as I picked up 1000 DRG lead bullets to use with titegroup powder. Lots of information from othe CZ users on that combination. Still, good information to log in case someone else needs it.
 
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