45 acp correct COL


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costantino
November 27, 2006, 09:22 AM
Hello there,
I own a Norinco 1911 (could not afford anything better than that here in Italy, very expensive for american imports :( ) and I have a few doubts concerning COL factor depending on the bullet I use. The first issue is that most american brands are not available so I have to stick with local bullets both in lead and jacketed therefore available reloading data in american litterature does not neccesarily apply. I currently have 230 grains LED ROUND NOSE 226 FULL METAL JACKET ROUND NOSE also. As a rule of thumb, at least with my 9mm, I would set up my Dillon 650 dies using as a sample a factory winchester fmj bullet in order to set up seating and crimping (I would raise the platform and start turning clockwise the dies until I would feel some resistence and then tighten the lock ring). This process as worked fine so far with the 9X21 but with the 45 ACP I get feeding issues from time to time. I use 5.9 grains of vihtavuory propellent which is the starting charge (I believe it tollerates up to 6,4 grains in 226-230 grs bullets). at 32 mm COL (1.259 inches) the finished round doesn't "fall" really easely in chamber. At 31,4 (1.2362 inches) things go better but not perfect. What would then be the minimum and maximum COL for 45 ACP assuming that I would test it always with the minimum charge to stay within safe parameters? How does COL change between Flat point bullets/round nose etc? Thank you for your help.
Regards,

Costantino

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Steve C
November 27, 2006, 12:40 PM
If your loaded rounds will not drop in and out of the chamber easily (with the barrel removed) then it is hanging up some where. Most likely solution will be to increase your taper crimp a bit to bring in the case mouth, if any of the belling is left it can hang up in the chamber. If the case is bulged during reloading it could be too much pressure during seating from not enough expansion and belling OR oversized bullets. A Lee Factory Crimp die will eliminate both these problems and may be worth getting if you can't get the rounds to feed properly with your current dies.

Your OAL should work fine. Max OAL for the .45 ACP is 1.275 inch but depending upon the bullets shape will depend upon how deep it must be seated. Some bullets have less taper and others have a squared shoulder that may require deeper seating than a typical factory round. Check the loaded cartridge in the barrel to make sure the bullet isn't contacting the rifling and the case fits properly. Use a factory round as a standard to see where the case base should be in relation to the barrel hood. If you find the bullet is contacting the rifling and keeps the round from chambering properly then seat the bullet a bit deeper and recheck until the round chambers properly. The minimum OAL is also determined by the bullet shape. Square shouldered bullets need to be seated so the case mouth is just under the shoulder. Round nose bullets need to be seated no deeper than where the case mouth and bullet taper start. I've found that usually where the case mouth is just under the bullets shoulder or start of taper works best.

Ares45
November 27, 2006, 03:54 PM
First check your crimp. .469-.471" is a good rule of thumb.

Trial and error should tell you what your pistol likes. Load up a dummy round (no powder or primer) to Max SAMMI COL (1.275"). Remove the barrel from your gun and drop the dummy round in. If it doesn't seat fully in the chamber put the dummy round back in the press and bump it down .005" and try again. Eventually you'll find a length that fits your chamber. Once you find a length that fits your chamber you'll need to assemble the firearm and load the DUMMY ROUND in the magazine and chamber it. You may have to go even shorter if the dummy round won't feed from the magazine or the gun won't go into battery when fed from the magazine.

FMJ round nose bullets usually seat towards Max COL. My USP45 likes it's 230gr FMJ round nose at 1.265". Different shape bullets with different bearing surfaces will load shorter. My USP45 won't reliably chamber a FMJ flat point or semi-wadcutter until I get down to 1.205".

I'm sure you already know this but remember that anytime you decrease COL you increase pressure. Be sure to reduce your powder charge and work up again with the new COL.

Welcome to THR!

costantino
November 27, 2006, 04:26 PM
Thanks to Steve and Ares 45 for the answers. I spent I little time before posting this reply on my dillon. I prepared a dummy load with a FMJ RN 226 bullet and I did bump it down to 31 mm (1.220 inches) instead of the 32 mm (1.259 inches) suggested by the powder manufacturer. Now the load chambers really nice in the removed barrel. Do you think I can still use the minimum charge (5,9 grains of not-to-fast burning vihtavuory N340) recommended by the manufacturer or shall I decrease it since I am not respecting the recommended COL ? Thank again, also for the welcome note :-)
Costantino

JDGray
November 27, 2006, 04:36 PM
I like to take a fired case, not sized, and insert a bullet until it just starts, and push it into your barrel, seating the bullet. Carefully measure the oal, then subtract .010-.015 for clearance. This is the max oal for that particular bullet. Also be carefull not to over crimp with lead bullets, may create a bulge. Be sure your not shaving lead, also, while seating.(not enough bell) Good luck! And welcome to THR:)

Ol` Joe
November 27, 2006, 05:45 PM
Do you think I can still use the minimum charge (5,9 grains of not-to-fast burning vihtavuory N340

You should be fine with that charge. VVn340 is a slow powder for the 45acp and with the low starting load you are shooting the little change in COL shouldn`t cause any problems. Just watch for pressure signs if you work up from the load you are at and enjoy.:D

Bronson7
November 28, 2006, 08:54 PM
Your seating depth will pretty much be determined by the bullet length/style. What I mean is that I load 200 grain round noses much longer than 200 grn round nose flat points (1.190"). If you have several styles available, you can measure their length and with some very simple math, come up with an acceptable and safe load using a known good round as a reference. If I have two cartridges with different styled bullets and one is shorter than than the other, that's not necessarily a bad thing. OAL is important when comparing like rounds because it indicates too much bullet is in the case. Remember, when trying to develop a load with different styles, bullet insertion depth is the key. You can seat at the same depth (not oal) as your safe reference round or less. A lot of times you can see the difference right off the bat by looking at the bearing surface. The 200 grn RNFPs I mentioned earlier have a shorter bearing surface than the 200 grainer round noses, so I know I'm safe using the same powder load. Of course, this doesn't mean accuracy or feeding will be the same. Any deviation from the powder load in your reference round when using different style bullets should be approached with caution keeping an eye on pressure signs. What I've written only applies when using the same weight bullets. I've only mentioned this because of your question regarding the hollow points versus the round noses. I didn't intend to be so verbose. I just couldn't stop myself.:)
Bronson7

Sunray
November 29, 2006, 01:29 AM
Norinco .45's are ok. Follow your manual religiously and taper crimp only. The OAL of the case is important too. Not just the loaded round.

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