Taper crimp measurement for .45 ACP?
I've been using the barrel from my 1911 as a gage to test my reloads, and in order to get my reloaded rounds to chamber like factory ammo I have to set my taper crimp to .468 or .469 inches. I started with .471, but some of the rounds required what I consider a significant amount of force to fully chamber. Is this normal, or is it possible that the barrel of my 1911 is a little small?
If you are not checking your cartridge length you will get an inconsistent crimp and this could be causing your problem. Case length is important. That being said you should be able to use most shells without trimming. I set up my die so that I get a firm grip on the bullet without denting it. I've had no feeding problems doing it this way. I don't normally measure the actual crimp. It is possible your chamber is a bit tight too. What I discribe above is good for general use. If you are aiming for absolute accuracy then what you are doing is the right way. In any event, every chamber is a bit diffrent and you will have to figure out what works best for your pistol if accuracy is your chief goal. As long as your rounds are at or slightly below listed spec.s everything should work fine.
Thanks for the reply gmaske. I asked the same question on another forum, and most there didn't provide much useful info. I admit that I should have measured the cases and only trimmed them if it was necessary. I did measure all my finished cartridges since I only loaded 20 rounds, and all were within .001 of 1.272 inches. I've been told on other forums to seat my bullets deeper, but no one can tell me how deep is too deep. Is 1.260 to 1.265 usually ok or should I stick with something closer to 1.275 for 230 grain, round nose FMJ bullets?
The info you are asking for will be clearly stated in the load charts you should be referring to.
Originally Posted by myersn024
We can not confirm your numbers without referring to load charts ourselves but not knowing what bullet, powder etc prevents our doing that.
You need to get at least 1 reloading manual. Lee publishes a good one at a reasonable price.
All powder brands provide load charts via the internet and or US Mail. The following powder companies are a good place to start.
Crimp diameter of .470 is not excessive. Other aspects can cause a poor fit as well such as less than full length sizing.
Do yourself and the guy standing next to you at the range a big favor by purchasing and reading Lee's manual prior to loading any more cartridges.
Sounds like you need a good loading manual. 1.275" COAL is the maxium industry standard for a jacketed ball bullet. Check Winchester White Boxes and you will see what I mean. The mouth of the cartridge should measure .470" to .472". Remember the .45acp head spaces off the rim of cartridge in the chamber. Crimp it to much and the shell will be in the barrel.
Using your barrel as a gauge is OK and the cartridge should fall in free and be flat with the barrel and fall out free. If the cartridge falls below the barrel you will suffer misfires. If it is above the barrel it will not go into battery and you could have a Ka-Boom. Hoped this helped.
As TOF said you need to get a good manual and the Lee 2nd Addition would be a good one to start with. It would answer the questions you have quite nicely and the price is very atractive too. Reloading is pretty easy but you need to know were the white lines are on the road.
Originally Posted by myersn024
I have the Lyman manual and have read through it, but as with most things, books say one thing while people say another. The Lyman manual doesn't really give a range for anything; it's one measurement, and that's what everything needs to be. i've read all over the net where guys say to taper crimp to .469, while others say no smaller than .471. I was just asking around trying to get some more info from people with practical experience. I've got the Lee manual on order, and it should be here in a few days.
That being said, I think my major problem was that I chamfered the ends of the cases too much.
The Lee manual will provide a dimensioned drawing for each cartridge for which load data is included. It will also provide an overall length for each bullet/powder combo listed. COAL will vary to some extent with different powders and brand bullets. Lee uses data from the bullet and powder companies in their chart so you get a broad spectrum of data. Books by a Bullet Mfg. will only relate to their bullets so have limited value regarding load data. Same for powder.
Originally Posted by myersn024
It discusses crimp but does not list crimp dimension for each cartridge.
In general Semi Auto cartridges are lightly crimped at most. I simply straighten out the flare generated prior to bullet placement.
Typical case wall thickness is .010". With a .451" Dia bullet. If the case is straightened out the OD will equal .471 give or take .0001 or so.
Anything less than .471 indicates either thin brass undersize bullets or the case pressed into the bullet (true crimp).
Your question regarding COAL can not be properly answered without knowledge of powder type and bullet type used.
Bullets of equal weight can be different in length resulting in different size powder cavities end result of which is different pressures.
I reccomend you follow the recepies in load manuals more closely than us internet groupies although we can help in some areas.
Have fun and stay safe.
I'll throw a few curve balls in here just for fun
In the Lee manual it will give you a mimum legnth on a bullet powder combo that you shouldn't go shorter than. You can go longer up to the maximum cartridge legnth on most bullet powder combo's as long as the bullet it self doesn't engage the rifling when chambered. That can easily be checked using the barrel as a gauge. Barrowing from the rifle boys you can improve accuracy slightly by seating the bullet in the case just a few thousanth short of engaging the rifling. This is a mighty fine point that will only help an otherwise perfect round. I'm not sure it is really worth it as this is part of a whole list of other fine tunes such as each bullet being exactly the same weight and each charge of powder being exactly weighed and so on and so on. If you were in to target shoots it might be worth the extra effort.
As you work with the data in the manuals you'll begin to see what will work. It's good that you are trying to get things right. As TOF pointed out if the bullet is the right diameter and your crimp die is set right it is pretty much a no brainer given the right case legnth. The only stupid thing about questions are the ones you don't ask.
I loaded up a couple of dummy rounds yesterday with the COAL set to 1.265 and they seemed to chamber better than the longer ones that I began with (1.270-ish). I thought about trying a few dummies at 1.260 just to see if they were any better, but I haven't taken the time to try them put them together yet. For the dummy rounds at 1.265, I also didn't trim the cases. They were within the maximum length, and they seemed to work better than the cases that I trimmed to .888. However, I didn't take into account the longer cases and they got pretty expanded by the expander die and it took a lot of crimp to get them completely flat......which really skewed the results of my test. I'll bust things back out later tonight and see what happens.
Thanks again for the info, guys, and keep it coming!
Ok, When you flair the mouth of the case you want to expand it to were the bullet just starts and no more. If you over expand it will wear out the cases and you will start to get splits in the top of the shells. The bullet should sit on top with just a slight bit started in to the case before you seat them with your seating & crimping die.
From my own experience, I suggest that checking the length of the brass is pretty important. Some once-fired brass I've measured were already too long!
What I've always done, and it has always worked to my satisfaction (see below), has been to cut each case to the minimum acceptable length. (No, I don't remember the actual measurement—the trimmer is properly set up from a long time ago, and I just use it as-is.)
Then, when I taper-crimp each finished cartridge, I just run it into the die until the case-holder contacts the die's mouth. I haven't the slightest idea at what diameter the case mouth finally ends up.
How do I get away with this irresponsible behavior?
It's because I shoot a M1911A1 Colt's Government Model, that's how.
You can talk until you're blue in the face about how the .45 ACP cartridge headspaces on the case mouth, but the reality of using a 1911 is that the cartridge is really held in position by the extractor! As long as the case mouth isn't too large to fit in the pistol's chamber, everything works reliably and well, every time.
Now, remember, this only works in a 1911 with an internal extractor. It's not for the S&W version, I suspect.
And I don't know how it'll work in other, non-1911 pistols. But it works just fine in my AMT .45 Backup, and it has an external extractor.
Well, I put together a few dummy rounds that were 1.260 inches long, and they chambered great without having to put very much crimp on them at all. In fact, I'm fairly certain that one of the rounds didn't get any crimp at all (or at least it didn't feel like it when it was in the press). Unless anyone can give me a good reason not to stay with that length for these particular bullets, I'm going to leave the dies set up for that length.
Thanks again for all the advice guys!
1.260 is certainly a valid OAL for .45ACP cartridges with certain powder/bullet types and weights. It should yield rounds that feed well when using FMJ round nose bullets.
Originally Posted by myersn024
The question remains however; are you following a tested set of data from a bullet or powder companies load chart or did you simply hear or read from an individual that 1.26 might work for you.
As an example, the Vihtavuori manual lists overall lengths from 1.130 to 1.260. There are good reasons for the variations in length.
If you were to use powder charges and bullet specified for a 230 grain HP with the 1.130 OAL you just might blow your hand off. If you use the powder charge and bullet which is specified at 1.130 OAL but set OAL to 1.260 you might end up with a bullet stuck in the barrel which if followed by a second shot could blow your hand off.
Hand loading if done properly can be fun and save some money. Done wrong it can be extrordinaly expensive.
I caution you to only load per well established data untill you gain considerably more experience than your posts indicate you have.
I have been laoding 45 ACP for over 20 years, probably over 40,000 rounds. I also build and repair 1911s for customers incuding for competition. It is a very easy cartridge to reload. For most use, a round that will function in the magazine should be able to chamber in the barrel. Taper crimping should just barely crimp the flair. If you crimp too far, it will expand the bullet ahead of the crimp and make chambering more chancey. In my expeience, when someone is trying this hard to load a round that will chamber reliably, then the problem is more likely in the barrel. In every gun that I repair, I drop my chambering reamer in, and it usually will cut a little out of the forward end of the chamber. Since the reamer is cut to SAAMI specs, this means that the chamber was too small. The reamer also cuts a small leade into the rifling, allowing the round to seat without driving the bullet into the lands. This is the way the chamber should be unless you are only going to shoot 230 round nose. A gun with the chamber properly cut will chamber any bullet on the market. This is not creating a "modified" gun, only putting it in proper specs.
Last week I cut a chamber on a new Springfield Armory. The owner was going through all the same motions, changing bullets and crimps, measuring things down to half thousands, etc. Two minutes with the reamer and chambering problems were solved.
Find a gunsmith that can recut the chamber. It will save you a ton of headaches. I have several 1911s. One has ove 20,000 rounds through it with no jams.
Send the barrel to me. You pay postage and I'll fix it for $10.00. If you send the slide and barrel, I'll adjust the extractor also, no extra charge. The extractor does not hold the round for primer strike. In a properly set up pistol, you can remove the extractor and still shoot. No one but you will know that the work had been done.
The biggest problem that I think I'm having is that the bullets were bought in bulk, and I don't have a clue who the manufacturer is. Because of that, I'm trying to find how THESE bullets work best in my gun. Factory rounds will drop right in and out of the barrel without any problems, and my 1911 will shoot pretty much anything without any hiccoughs. When I started loading up these rounds, I started with the length recommended by my Lyman manual since I didn't know anything about the bullets, and that length was 1.275. I was trying to do things by the book, and I had a little trouble getting the rounds to slide in and out of the barrel like factory rounds do. That's not to say they wouldn't go in and come back out. So, I've been putting together dummy rounds of varying length to see if shorter rounds work better, and so far the shorter ones (1.260 - 1.265) take less crimp than longer ones (1.270 - 1.275).
All that being said, I'm not just blindly loading rounds seeing what will happen. I've only loaded 20 live rounds thus far, and I've been trying to find the optimal measurement for the bullets so I don't have to over-crimp them to get them to seat properly.
What type bullet are you dealing with? LRN, JHP, FMJ, 230 GR, 200 GR etc.
The only reason overall length should prevent it from fitting your chamber would be if the bullet is hitting the rifling before the case is fully seated.
Try setting the crimp just enough to straighten the wall out. Then back off on bullet seating depth such that the OAL is .1" longer than max. Drop the cartridge in the chamber and measure how much the cartridge protrudes from a fully seated position.
The resultant measurement is how much deeper the particular bullet must be seated to prevent it running into the rifling before seating.
Using the same cartridge, progressively seat the bullet deeper till it fits the chamber properly.
If the cartridge never seats properly with the bullet seated deeply you are having problems with diameter. If at 1.260 give or take a bit it suddenly seats acceptably your problem is insufficient lead (clearance cut) in the barrel prior to the rifling.
If you determine the rifling is the problem you can either seat the bullet deep enough to accomodate it or have the chamber and lead reamed.
If you find the bullet must be seated significantly deeper than your load table calls for I would have the ream job performed.
How long have you been reloading?
I've just started reloading. I loaded 20 rounds last weekend, and when I was finished I decided to try them in the barrel of my 1911. Some chambered alright and others didn't. So, on the advice of more experienced reloaders, I stopped making live rounds and tried to figure out what I was doing wrong. The bullets that I have are 230 grain, round nose FMJ. I've weighed and measured several of them, and they've been pretty much right on. Most have suggested that if I have to put a serious crimp on them to get them to chamber that it means that te rounds are too long. Based on that, I did some experimenting and found that with these particular bullets that something in the 1.260-1.265 range works better.
I don't really understand why there's so much focus on overall cartridge length here, when the really important measurement is brass-case length. Without the bullet. Just the case.
Whether the loaded round fits its chamber, whether it properly seats in the barrel, depends more upon case length than upon overall length.
The amount of taper crimp, too, is dependent upon case length, and not upon overall length.
For that matter, chamber pressure is dependent upon case length, rather than overall length. If the case is too long, it will not have enough chamber room to properly release the bullet, and overpressure will result.
Look at case length, folks.
Here's a tool you might want to add to your bench. It's a Case Gauge and it cost about $12.00. You will not have to take your pistol apart to check your new rounds. It is your pistols chamber cut to spec. Nothing goes in my pistol without going through this little jewel. I am loading about 1,500 to 2,000rds a month for my family.
Search tags for this page
45 acp crimp diameter
45 acp taper crimp diameter
45 acp taper crimp measurement
crimp diameter for .45 acp
how much crimp on a 45 acp
how much taper crimp on 45 acp
how to measure case crimp on 45 acp
how to taper .45 reloads
how to taper crimp 45 acp
measurements for 45 acp
reloading 45 caliber can not get the same diameter of bullett after using tapered crimp
taper crimp 45 acp
Click on a term to search for related topics.
» Springfield Armory
» HGF Sponsors