.45 ACP question

[Clovishound]

I ordered some coated 200 grain RNFP bullets to use for .45 ACP. I was going to seat them with the mouth right at the base of the canelure, but discovered that they don't pass the plunk test. The data I have is actually for a SWC. Min COAL is 1.225. In order to get them to reliably pass the plunk test, I have to seat them to 1.215.

My first thought is that the RNFP is probably a more squat bullet than the SWC. None of my manuals list a load for this specific bullet. I see loads for a JHP that have a much deeper seating than this. I suspect that I can seat these much deeper than 1.225, but I like to have hard data.

The other issue is that if I stick with the current 1.215 length it puts the mouth right in the upper part of the canelure. I would have to seat them much deeper to get over the canelure and have the mouth supported.

The coating on these is a little bumpy, and I'm wondering if that may be what is causing them not to pass the plunk test. I usually have them pass pretty close to max COAL with a smoother bullet, like coated or bare cast.

Any help in steering me to the right info would be appreciated.

 

[Clovishound]

After some more research, I finally found some data. Alliant has a recipe for a 200 RNFP using Sport Pistol. They list the COAL as 1.175. I checked their recipe for the 200 LSWC with the same powder. It lists a COAL of 1.235.

I would probably be OK to just load with Universal down to around 1.175, or I could play it safe and get a bottle of Sport Pistol and use that.

 

[Chuck 100 yd]

A call to the bullets maker or the molds maker seems to be in order here.

 

[NikA]

Lyman cast manual lists both a RNFP and a SWC for .45 ACP. Max loads are about the same (exactly the same for Unique); COAL is 1.23-4" for SWC, 1.16-7" for RNFP. If you're interested, I can look up the mold numbers and post them so you can compare them to the bullets you're loading. The relevant metric here is basically where the back of the bullet is in the case; if you have both types, you can measure their length and figure out what the OAL should be for the shorter bullets.

 

[SweetWilliam]

I would just keep seating them a little deeper until they pass your plunk test.
My Ruger cmd is real finicky with c.o.l.
I had to seat the bullets a little deeper than recommend. Once I did that I never had anymore problems.

 

[Gator89]

SweetWiliam is on target, seat 'em deep enough to plunk and feed in/out of the mags.

 

[mikld]

For semi-auto use, disregard the cannalure. Set to a depth that allows a good plunk test and very lightly taper crimp (just enough to remove any flare). When starting with a new component/bullet, always start with a starting load as seating depth can increase chamber pressure...

Each bullet design/shape will have a different listed OAL...

 

[Ka6otm]

SweetWiliam is on target, seat 'em deep enough to plunk and feed in/out of the mags.

Correct. The few thousandths deeper seating won't make any practical difference.

 

[Clovishound]

Well, I ended up seating them deep enough to catch the upper side of the canelure to support the mouth upon crimping. I am not happy about putting the mouth over the canelure, with no support. This still puts me within the COAL listed by alliant for this style of bullet. I had to increase the light crimp a little to keep them from setting back. I even took my calipers to the range and measured the first round in the mag. After shooting about 5 rounds, I pulled the first round and measured. They were shrinking by a couple thousandths. I don't want the odd slightly looser bullet setting back significantly. I also am loading them near start loads to minimize any pressure issues. I ran a handful of them last week and they seemed to shoot fine, so I went ahead and loaded up a quantity that I will shoot later today.

Next go round I will order the SWCs. I have loaded SWCs before for this gun with success, and apparently he has the new NLG mold in for the SWCs. No lube groove or canelure. I will be glad when these are gone and I can move on to a better suited bullet.

 

[Enigma]

I've been reloading .45 ACP since 1976, and I don't think I've measured OAL but once or twice during that time. Well, that's probably an exaggeration; let's just say that I don't obsess over OAL. Seat the bullet to a length where it feeds from the magazine with no problems, chambers easily, and the slide goes into battery without difficulty. As long as all those conditions a re met and there are no signs of high pressure, you're golden.

Question for Clovishound: what type of crimp are you using, and in what gun?

 

[Clovishound]

I'm using the standard taper crimp from a set of Lee dies. I'm seating and crimping in the same step, as I use a powder cop die as a last ditch safety measure. When initially setting the crimp, I normally start with a light crimp and increase it, if needed, until I have no setback issues. In other words, I use the lightest crimp that will keep the bullet in place.

I'm loading for a Springfield Range Officer, full sized.

If it weren't for the canelure, I would have just seated them about 10 - 20 thousandths past the point of reliable plunk testing and called it good. As stated before, I was nervous about the mouth being directly over the canelure, and unsupported. This is the first time I have had a bullet that needed to be seated even close to the minimum COAL. Of course, since the data available was for an SWC rather than a RNFP, it is not surprising.

I shot about 100 of these loads on Monday and they seemed fine. Accuracy was good and still no signs of overpressure. Unfortunately, with a low pressure round like .45, the first sign of overpressure may well be the magazine blowing out the bottom of the pistol.

 

[mikld]

FWIW; the "crimp" on a semi-auto round does not enter the cannalure. A taper crimp removes the flare and very lightly adds to the neck tension. You'll be better off to forget the is a cannalure there and just remove the flare from the case mouth with a taper crimp die. Crimping into a cannalure or crimp groove can result in headspacing problems and FTFs

I just reloaded another 100 rounds of my "just in case" 45 ACP ammo. After I seated the bullets a 230 gr, FMJ and before a "crimp", I pushed the case/bullet against the bench. Measured before and after and with a good push the bullets did not move. I then ran the cartridges through a taper crimp die to clean up any flare and plunk tested about 25%-30%...

 

[Clovishound]

FWIW; the "crimp" on a semi-auto round does not enter the cannalure. A taper crimp removes the flare and very lightly adds to the neck tension. You'll be better off to forget the is a cannalure there and just remove the flare from the case mouth with a taper crimp die. Crimping into a cannalure or crimp groove can result in headspacing problems and FTFs

OK, maybe I am understanding what you mean, but this seems like conflicting advice. You say the crimp on a semi auto doesn not enter the cannelure. You also say that crimping into a cannelure can result in headspacing problems.

The reason I am concerned about the cannelure is I don't want the mouth to fall over the cannelure and perhaps the crimp will push it in too far, or the action of chambering will push it into the groove and cause the round to seat too deeply. My primary choice of bullet seating for this bullet would place the mouth directly in the middle of the groove. I went ahead and seated deeper until just past the end of the cannelure where the mouth is supported.

 

[Throckmorton]

I"m confused about what you are calling a 'cannelure.' I've never seen cast bullets with a cannelure,.. they have a lube groove,and if they're designed for a Colt load, a crimp groove for a roll crimp.Can you show me/us a picture of the bullet ?

I've loaded at least a half dozen different brands of cast bullets for my 1911 and hve learnd that oal's shown in the book are more of a suggestion than a rule. Cast bullets are just 'different' than jacketed,that way.

the bumpy coating on the bullets could for sure cause grief in getting them to plunk, .

 

[mikld]

Cannalure/crimp groove, whatever, if the case is rolled at the mouth there is a good chance of the case not headspacing correctly. Semi-auto ammo headspaces/seats on a ridge in the chamber and needs a square "lip" to determine how far the cartridge goes into the chamber. If there is no "lip" or square edge, the cartridge can enter the chamber too far.

Don't overthink the neck tension or "unsupported case mouth", as the 45 ACP has been reloaded like this for over 100 years quite successfully. (Only 20 years for me. I did not "crimp" any of the thousands of 45 ACP rounds I've reloaded. I just removed the flare and left enough "lip" or square mouth/edge to headspace.)

 

[Clovishound]

Here is the link to these bullets in cast. The coated are from the same mold, only with a coating.

http://www.summersenterprisesllc.co...-hard-cast-lead-bullet-p/45-200grrnfp-500.htm

I have always used the two terms interchangeably. Perhaps there is a difference. I do notice that on cast bullets the groove for crimping usually has a beveled edge on the base end of the channel. On plated/jacketed, they are usually serrated and don't bevel on either edge. Since they both have the same purpose and generally similar construction, I have never made a distinction.

 

[mikld]

Yep, crimp grooves are on cast bullets and are designed in and the bullet drops from the mold with the crimp groove in place. A jacketed bullet uses a cannalure, or a groove knurled, turned on the OD of a finished bullet. For 45 ACP loading ignore both the crimp groove and/or the cannalure...