1911 lube in chamber behind case mouth?

[mistermog]

Well, I took a RockIsland 1911 out this past weekend and came up with a pretty bad issue. After less than 10 rounds I am getting a lube/gunk buildup in the chamber around the casemouth area that keep the next round from fully loading and the gun doesnt go completely into battery.

Pulling the case out gives about a 1/8th inch wide black ring of gunk on the outside of the case mouth down the wall. Not sure where this comes from or why. The slide is not easily operated at this point, as it feels like its jammed, which technically it is from lube against the case.

I lube and size at .452 and not sure whats going on. I'm using a Lee truncated cone OAL at 1.225" so it will clear the grooves. Using the white label 2500+ lube.

There is no lube on the outside of the case or bullet when I put it into the mag.

Anyone ever seen this or had it happen?

[popper]

Somewhat normal. Not enough pressure to seal the brass/chamber; improper sizing; unlocking to fast, maybe a weak recoil spring?; lube too soft.

[mistermog]

Hmmm they are running about 800 fps, quickload is estimating about 15,500 psi chamber pressure. There are maybe 500-600 rounds through a brand new pistol, and I've shot reloads through it before without a problem. Something with this load makeup that it doesnt like.

I could see the brass not sealing, I do load them light. Any other way to see if thats the case?

[Moonie]

What exactly is your load?

[mistermog]

234 grain .452 Lee TC (actual weighed out average with air cooled wheel weights)
sized to .452
1.225" OAL
5.0 gr win 231, +- .1gr (using lee pro auto disk so theres a tad bit of variance)
Not using LFCD.

[geargnasher]

Not uncommon. Generous chambers and the timing of boolit obturation, case obturation, and breech unlock contribute to this. Try leaving a little flare on the case, just "crimp" enough of it off to allow the ammo to pass the "plunk" test in the chamber. I shoot that boolit in three 1911s and I tend to load near .1.250", just to "kiss" the cone when chambered and don't have that problem. I don't think switching lubes will help you, but a softer lube might, you'll just have to try it and see.

Gear

[prs]

Well, you could always resort to tumble lube. I use that boolit too, but I'm kinda new to 1911. I use a very soft homemade black powder lube and no problems and I have used Reclluse and straight Lee tumble lube with no problems; except at first I had some failures to chamber due to being ignorant of the plunk test. My 1911 is an SR1911 and seems to have abrupt onset of rifling and my OALs maybe a tad bit shorter than yours or Gear's.

prs

[Cherokee]

I have shot a ton of those cast boolits and do not have that problem with 4.6 to 5.3 of 231 seated a 1.185" and taper crimped at .471". I use Lars CR lube. Works in Taurus 24/7, XDm 5.25, several 1911's. I suspect it is a chamber/throat problem.

[mistermog]

Well I found out what the problem is I believe.

Doing some plunk tests didnt clue me in on this but apparently the very edge of the lead above the case mouth is getting shaved a tiny bit from the edge of the chamber where the case mouth sits... believe thats the throat?

Anyway, consarnit! Guess its back to the drawing board with seating depth with this mold. (or a tiny throat job?)

[Nocturnal Stumblebutt]

mistermog, my RIA 1911 does the same thing, I use a soft lube now, and have tried various lubes, boolits, crimps, etc. Unfortunately, it is, from my experience, the result of the generous chamber, and the relaxed recoil spring, so its a catch 22; load to lower pressure and the case doesn't expand; load to a higher pressure and it unlocks too early.
Don't get me wrong, I love my Rock Island and shoot it often, though mine doesn't gunk up as fast, I start getting problematic buildup between 50-100 rounds, depending on the day, so I just take a bore snake with me and run it through when I have an issue, I usually only need to use the bore snake twice.

[mistermog]

Well, i was doing some calculations and found out I can seat to about 1.13" (Yes I know its tiny), and quickload still estimates right around 760 fps with 4.13gr of Win231.

I'm not sure what chamber pressure is really needed for 45 to expand 100% but it looks like I have some room to work down there at the low end with this bullet design.

[runfiverun]

simple nuff to change a spring...

[mistermog]

what would a spring have to do with anything?

[HighHook]

Try a stiffer spring maybe 20-24 lb. if that doesn't work you can polish the frame ramp and barrel or have it done for you. Some arent as cast friendly as others. The magazine is also where you can look it has to have the right angle.:coffee:

[mistermog]

oh its not a feeding issue, its a the bullet is too fat for the end of the chamber thing.

[Blammer]

my RIA does the same thing. I just changed projectiles to one that had more room by the case mouth. Like this one

http://i54.photobucket.com/albums/g81/blammer8mm/Cast%20boolits/DSCN7180.jpg

it just delayed the gumming up to about 100 rnds instead of 25 with other nose profiles.

[45fan]

Not uncommon. Generous chambers and the timing of boolit obturation, case obturation, and breech unlock contribute to this. Try leaving a little flare on the case, just "crimp" enough of it off to allow the ammo to pass the "plunk" test in the chamber. I shoot that boolit in three 1911s and I tend to load near .1.250", just to "kiss" the cone when chambered and don't have that problem. I don't think switching lubes will help you, but a softer lube might, you'll just have to try it and see.

Gear

Gear I see your OAL is 1.250, the OP says his is 1.223, I finally cast my first batch of boolits with COWW and then loaded them with with HP38 powder to OAL of 1.230. I wasnt sure how long I should load them too. My loading manual shows a max and min load length and I finally decided to take a measurement of some factory made ammo and copied that, but how do you know what is the "best" OAL. Does this "plunk" test you speak of help determine that? Or what exactly is a "plunk" test what function does it serve and how does one perform this test?

I didnt have any issues shooting my first batch of ten test cartridges I made, but I just may have been lucky. This is one instance where I would rather be good than lucky though.

[HighHook]

Also make sure you put the proper tapper crimp on the case. It is a separate die...

Load 5 clips with 5 rounds each of different oal's and powder weights. after each 5 inspect the chamber and run a quick swab out of the barrel.

Then try some with 4 gr of bullseye.

Sometimes powder and lube don't mix...Keep us posted

[runfiverun]

the boolit blammer shows was the worst one i tried i understand a lot of people like it [shrugging]
maybe lubing just one lube groove woulda helped my accuracy [again i dunno]
the rn,and both swc molds i had done better so i sold it and one of the swc molds

the stronger spring does a couple of things for you.

delays the movement of the slide for one. [problem here]
closes the slide a little more forcefully for another. [also a problem here]
stops the battering of the frame from a little stouter load, which would help case sealing. [stouter load would help here]

[geargnasher]

Field strip and remove barrel. Hold barrel chamber up. Drop "dummy" round into chamber (no primer or powder). Cartridge should fall in to flush or just below flush with the barrel hood, and fall out under it's own weight when the barrel is inverted.

Size a case and flare it as you normally would. Test fit it in the chamber and crimp out the flare gradually until it will fall in under its own weight. Measure the case mouth and record it.

Make your dummy and seat the boolit long, leaving the flare per above. Keep doing the plunk test and gradually seat the boolit deeper and deeper until it's just below flush of the hood. I like about ten thousandths clearance. Most .45 ACPs headspace off of the extractor rather than the case mouth due to long chambers and short brass, I prefer mine to headspace off of the boolit.

After you get a dummy to pass the plunk test, make several identical ones and cycle them through the gun by hand from the magazine.

Your gun comes with the only case gauge you need. The only thing the book COAL is good for is establishing a safe minimum for the data listed due to internal case capacity.

Gear

[HighHook]

Great info Gear!



To the OP, If you use live stuff please remove the firing pin First!

Don't ask me how i know...

[geargnasher]

Oh, and plus 1000 on the stouter spring. 18lb minimum, 20 is probably better although it's harder to rack on you pants leg in a pinch.

Gear

[geargnasher]

Great info Gear!

To the OP, please remove the firing pin First!

Don't ask me how i know...

I don't follow. Unless there's something about the RIAs I don't know, the pin ought to be plenty far up in the breech block during all of this and not interfere with the measuring.... Did you get the part about not using powder or primer for the "dummy" rounds? There's a reason for that, which it appears you may have unfortunately discovered..:bigsmyl2:

Gear

[HighHook]

Gear,

I was editing it while you were writing it. Got-it

[geargnasher]

Here's a good read: http://castboolits.gunloads.com/showthread.php?t=169880

Gear

[Linstrum]

Oh, and plus 1000 on the stouter spring. 18lb minimum, 20 is probably better although it's harder to rack on you pants leg in a pinch.

Gear

Interesting thread. Hmmm, how do you rack on a pants leg?

rl 1,151

[geargnasher]

Snag the sights/top of slide on the outside of your thigh, muzzle down, and push. It is considered bad form to shoot yourself in the leg while doing this, so please don't.

Gear

[runfiverun]

i've seen it done under the armpit and under the knee in a couple of circumstances.
when the slide was dropped on an empty gun then the magazine was inserted under some stressful situations.
and not just on a 1911.

[HighHook]

A magazine article years age long before the web i read. That John Browning introduced the grip safety of one of 3 reasons.

One being what is talked about here...

[fredj338]

I doubt 5gr is running 800fps, a bit under that. IME, W231 is just dirty w/ lead bullets. AC ww is probably a bit hard for that low a pressure, you are likely not over 15K. So softer bulelt may help some, mix pure 50/50 w/ clip ww.
OAL is ALWAYS gun & bullet specific. So regardless of what the manual says, it MUST fit your gun. IME, TCFP load quite a bit shorter than RN. The Lee is a close match to the XTP, most guns will not like OAL longer than 1.220"-1.230". The lower you go with W231, the dirtier it gets. ALox + carbon = gunk. I use CR or BAC, prefer CR.

[mistermog]

I do plan to run a bit more pressure on the next batch but from what ive discovered tonight, the bullet sized at 452 is JUST big enough to scrape on the mouth of the chamber.

(Probably the wrong word, but the part that catches the .45acp case mouth, the ring in the barrel etc)

It shaves off just a TAD bit of the boolit, which in turn brings a tiny bit of lube with it.

I know rock island's are made on the original GI specs in there, but what can be done?

Can a good gunsmith ream out a tiny bit of that chamber edge?

I ran a boolit down the chamber and hit it into the grooves a tad, and it definitely is not just the lands doing it, its the entire circumference of that chamber lip that touches the boolit.

[Fluxed]

I'd make a chamber cast and measure it, or have a gunsmith do it for you. After you know what size it is you can have the chamber reamed if its too small or out of spec.

[mistermog]

Its not so much the chamber, just the ridge that supports the case mouth

[geargnasher]

Yes, it can be reamed.

Gear

[mistermog]

Is that what a reamer would do? I dont think it needs THAT much taken off... maybe .001

That shouldnt mess with headspacing, just narrowing that ledge. could I get a tapered dowel with some polishing compound or something maybe?

[mistermog]

I found an image to explain the issue I think better than I can via words.

http://www.shootersforum.com/attachments/gunsmithing/1391d1094362133-45-acp-chambering-45chamber.jpg

this is from an old magazine i believe someone else mentioned somewhere.

Basically, the spot with the arrow. the diagram shows it should be .453, and I believe mine is .452 in this barrel... so wondering how I can polish out that little bit and i'd be golden.

I have shot .4515 sized boolits without ANY issue in this barrel, but I had to get a new sizer and that comes out .4525 or so

[Fluxed]

Past the tiny shoulder at the end of the chamber is a short straight cylinder and then a tapered throat that leads from the short straight cylinder diameter to bore diameter. Either or both the straight cylinder or the tapered section could be wrong. You can discover the situation by making a chamber cast to see and then measure your barrel's throat (the straight cylinder and the tapered section are the throat). Once you'd one this you can make an informed decision about altering the barrel. Or a gunsmith with a known good reamer can just ream it for you. It's better to check first and a good smith will do that for you.

[mistermog]

Yes theres another thread on here with a guy selling cerrosafe to make a cast of the chamber because im curious.

I dont know what exactly is going on but I think it is a combination of both going on. I was playing with the barrel a bit last night and a ring of lead came out, so that ledge is definitely hitting, and Im starting to think im just hitting the rifling too. So I dont think the rifling is very tapered either.

I'll know soon I guess. I don't know of any gun smiths in my area but might go try and find one after I do this when I know exactly what is going on.

Does a reamer take care of both of those issues at once?

[Fluxed]

If your chamber is smaller than the reamer, the reamer will remove some material.

As to the "ring of lead", you may be shaving a bit off the bullet as you seat and crimp it. The result is that you end up with a little "washer" of lead at the case mouth that will cause this kind of headache.

Are you flaring the case enough to be sure you are not shaving the bullet as you seat it?

[mistermog]

Yes it isnt on the case, its shaving it off the sides of the boolit upon chambering.

[geargnasher]

Brownell's sells a throating reamer, not sure what the dimensions are on the throat entrance, perhaps a call to them would sort it out. You might message BD, if I remember right he has one of those reamers and has fixed several pistols, he might give you a better idea.

I fixed a .38 Super Kart barrel with a tapered lead lap, but you have to be really careful not to scratch the chamber.

Gear

[mistermog]

I just picked up some cerrosafe that should be here by next week to make a chamber cast to see what I'm working with.

Im fairly sure that the chamber might be a tad small, and my boolits seemed to swelled a tiny bit to be .453 too... so looks like i have a bit of everything going on now.

[geargnasher]

Have you tried .451" boolits?

Gear

[popper]

Choose your GS carefully. I had some work done on a shotgun, was suposed to ream out the chamber. He just used a brake hone and did a poor job at that. Get references!

[mistermog]

Definitely popper!

Gear, sorta... I used a .451 sizer but they came out slightly smaller than that, which leaded a little bit so I sold that sizer and got a .452. Unfortunately that one is slightly bigger than 452. They seem to settle at .453ish after a couple weeks and I guess I didnt let them age long enough before I sized and lubed them and loaded em up.

[Linstrum]

With my Citadel copy of the 1911A1 I had trouble using 0.452" Lee truncated cone boolits so I machined my own 0.451" push through sizing die and haven't looked back. I can push around a gallon milk jug at about 30 yards and hit an 18"x24" target at 100 yards, so it doesn't do too bad.

rl 1,155

[mistermog]

tonight i took the firing pin out and ran about 100 through the gun. only 1 SLIGHTLY difficult one to chamber. a slight waxy buildup on the case mouth outside of the case again, but not very much.... so i guesss its a mix of powder fouling and SLIGHTLY shaving lead and wax mixing together?

why would it be doing it now and not cycling this well when firing?