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View Full Version : Help with .45 Colt Blowback.



Ed Gallop
07-20-2010, 09:16 AM
I've had a problem with extremely dirty brass for years in my Pietta Rough Rider 45 Colt. The brass is blackened, not smoked, and takes a very long time to clean. I think the cylinder chambers are larger, .488 to .489. than the Lee sizing dies are cut for.

Not sure if it matters but the chambers measure .451 at the barrel end and the barrel slugs at .453. Doesn't sound right to me. Should I have it bored to .453?

Brass sized with the Lee .45 sizing die measure .469 to .470 at the mid-section and .477 over the base of the .454 sized boolet.

If I fire new unsized Starline brass (474 to .475 mid-section) they come out much cleaner, smoked (not blackened), and cleans in a small fraction of the time.

If I don't size fired brass (.480 to .482) the .454 boolet slides into the brass without resistance and can be twisted by hand after crimping. The brass will load in the .489 chamber just fine. I haven't test fired those yet but suspect an improvement in blowback if the .475 new brass showed improvement.

I load maximum loads of 6.0 grains of Trail Boss behind a 250 grain sized .454 LRNFP so I'm not using light loads. Some say I need a faster powder, such as Red Dot or AA #2. I saw only a small improvement when switching from Unique to the faster Trail Boss but haven't tried a faster powder yet. I have my doubts though. Some say it is not enough crimp but it is well into the groove. I have ordered a factory crimp die but doubt that is the solution.

Just read that the RCBS .45 Cowboy sizing dies are larger than the Lee .45.

Can someone provide the diameter of brass sized with RCBS Cowboy dies?
If they size to .474 or .475 then my problem will be solved.

Anyone else with a Rough Rider have this problem? If not, what brass sizing die are you using?

zuke
07-20-2010, 09:38 AM
I'd say try a faster or more powder. It sound's like your case's aren't expanding enough to seal off the case mouth preventing blow-by.

Rocky Raab
07-20-2010, 10:11 AM
Several issues there. Gun dimensions are one problem, which you correctly identified. Small cylinder throats may be half the problem, and certainly don't contribute to accuracy.

I'd try neck sizing. Set the sizer die to size only a hair deeper than the bullet seats in the case. That allows the rear half of the case to remain closer to chamber diameter. That thick part of the case takes a lot more pressure to expand and seal, so leaving it at almost fired diameter will give it a "head start" to sealing.

Trail Boss is a low-pressure powder. It might not be generating enough pressure to seal the cases. Try some TiteGroup (which is designed to be position insensitive for light loads).

44man
07-20-2010, 10:14 AM
I'd say try a faster or more powder. It sound's like your case's aren't expanding enough to seal off the case mouth preventing blow-by.
This is correct. efficient burn and pressure will solve it. Low pressure will let powder carbon and lube go around the brass. Cowboy action loads are the worst. Zero recoil means filth.

Bass Ackward
07-20-2010, 10:20 AM
Not sure if it matters but the chambers measure .451 at the barrel end and the barrel slugs at .453. Doesn't sound right to me. Should I have it bored to .453?



If this is accurate then this can be the source of the problem .... or not. Either way, it probably needs to be corrected for low pressure cartridges if you want to do well with PB cast. You can do it yourself or use a guy like this.

http://www.cylindersmith.com/

It could be case anneal if new cases were better. It could be poor case neck tension on the dies too. Going to a die that doesn't size as much can actually increase the problem. So I would go there as a last resort.

With large chambers, you need a constant pressure level of that OVER that which is needed to expand your brass until the bullet has left the gun or it will leak. In essence, fast powder that peaks and begins to drop faster in a large bore diameter can amplify the problem.

After it is all said and done, my guess is that you have a confluence of issues contributing to your troubles. I would re-slug and then measure to be sure, then get reamed first if your first measurements are correct.

Harter66
07-20-2010, 11:37 AM
I have a RBH in 45Colts that started blackening cases too. It was when I started shooting my LEE 452-255 rnfp's changing from commercial cast. I tried Red Dot,then back to Unique. At max loads (from the Blackhawk section of the Lyman book I still had smoked cases. I was after an accuracy load to hunt with so I was short/neck sizing only at that point. I trimmed the cases back to 1.285 as they'd grown to almost 1.3 , still to no avail . In desperation I annealed the cases, I'd have expected case splits after 15 cycles and the last 5 or so being they were full tilt, problem solved no more smoked cases. I should add that my RBH has .480 chambers .454 throats and a .452 bore. Oh 1 more note those rnfps weighed in at 262gns and at over 1200fps were a handfull even with the over the frame"padded" Hogue grip.

fredj338
07-20-2010, 01:58 PM
Several issues there. Gun dimensions are one problem, which you correctly identified. Small cylinder throats may be half the problem, and certainly don't contribute to accuracy.

I'd try neck sizing. Set the sizer die to size only a hair deeper than the bullet seats in the case. That allows the rear half of the case to remain closer to chamber diameter. That thick part of the case takes a lot more pressure to expand and seal, so leaving it at almost fired diameter will give it a "head start" to sealing.

I agree w/ BA. Trail Boss is a low-pressure powder. It might not be generating enough pressure to seal the cases. Try some TiteGroup (which is designed to be position insensitive for light loads).
Trail Boss isn't really a low pressure powder, look at the position in a burn rate chart. TG will be even worse, burns very hot & you'll get case scortching. I think it's an issue of your oversize chambers & light loads. Not many ways around that. If you want to shoot light loads in the big cases, they will soot up as they are not going to expand to seal the blowback. I shoot RedDot in CAS loads, does the same thing. Softer brass cases, like RP, would help, a softer bullet alloy may help as well.

longranger
07-20-2010, 02:47 PM
Anneal the cases and shoot what you want, a pain for .45 Colt

Ed Gallop
07-20-2010, 07:17 PM
When I size fired Starline brass it is very rough and sticks in the expander die, requiring a lot of pressure to release. I think Starline brass is harder than Remington and Winchester. I like nice shiny looking unfired brass with as flawless cast as possible. Guess I'll have to be satisfied with with the discoloring of annealed brass if I want to get rid of the blackened brass that requires 10 times longer to clean. I've never annealed brass but have seen it done. I'll anneal a box (50) and see what happens with different powder and loads. I'll only anneal the area where the boolet seats. Should be a fun project.

I don't think my loads are light. How much more than 6.0 grains of Trail Boss with 250 grain CRNFP should I use? The charts indicate Trail Boss as a fast burn but I'll be trying the faster Red Dot next weekend. I will only neck size the brass and trying Trail Boss and Red Dot.

Thanks for the link to resize cylinder throats. I measured and slugged again and there is inconsistency. Don't make sense to size boolets at .454 for the barrel when the throat will size then at .451. I do need to have the cylinder throats bored even if it isn't the main cause of my brass problem.

Thanks to all for the good information. You were a big help. Ed.

Rocky Raab
07-20-2010, 08:18 PM
fredj, I respectfully disagree. Position on a so-called "burn rate chart" has nothing whatever to do with pressure (and not all that much to do with real-world burn rates, for that matter). IMR says that even a full case of TB can NOT exceed SAAMI pressures. That tells me it's a low-pressure powder.

TiteGroup was designed with cowboy action shooters in mind. It is position insensitive even in very small charges within large cases, and is quite fast-burning SPECIFICALLY so it will seal cases against blowby.

Ed, not to be a a smartazz, but if really shiny cases are what you want, load some up, polish the bejeezus out of them and them never shoot them. OR, would you rather have good-shooting ammo? Personally, I'd much rather have people ooh and aah at my targets - while I surreptitiously eject my dirty cases. But it's your call. (Yanking your chain a bit here, my friend.)

AZ-Stew
07-20-2010, 08:49 PM
Ed,

Your problem is that the brass isn't sealing the chamber. I think we've already established that, but it's the start point.

Take a look at the Hodgdon web site load data for the .45 Colt and 250 gr boolit. Trail Boss is one of four powders that develops less than 9,000 units of pressure with the start load. Most of the listed powders develop over 13,000 units with the maximum listed load, including Trail Boss. The issue here is not the max or min pressure, but how fast the pressure curve rises. A quick rise in pressure will cause the brass to seal the chamber immediately so that when the bullet clears the case the chamber is already sealed. "Slower" powders develop their pressure curve slowly, allowing the bullet to exit the case before the seal is made, thereby allowing powder gasses to flow back between the case and chamber walls. Faster powders, indicated by pressures over 9,000 and preferably higher, will create a seal before the bullet clears the case, preventing gas flowback.

Look at WW AutoComp, IMR 4756, IMR-PB and IMR 700X for "faster" powders. I can tell you from experience that IMR 7625, a slower powder by my estimation, and on par with your Trail Boss, will blacken my .41 Magnum cases with my preferred load of 6.7 grains behind a 210 cast SWC.

Now, you'll have to peruse the data to find a sealing load that provides the velocity you want, but I think looking for a powder with a steeper pressure curve may help you with the case blackening.

Regards,

Stew

(P.S. This was posted before I saw Rocky's last post. I started the reply, then had to go deal with the Census taker. When I hit "post", his was already there. I think, in a round about way, we said pretty much the same thing.)

smkummer
07-20-2010, 09:04 PM
I shoot Colt powered loads only even in my Colt 45 Anaconda, as for now I don't need the extra power. I found that sizing to just below the "neck" stopped the sooting in reduced pressure loads. The only unique loads I am using are about 9.0 grains behind a Lyman 454190 bullet (250 grains and unsized at .454). This gives me 900 FPS out of a 7 1/2 barreled Colt. I am also using that behind a 200 FP bullet for the same velocity. If I want 800 FPS or lower, I am using 6.1 grains 700X or Red dot. As others have said, its improtant to keep pressures up to do away with smoke. So its your choice, resize fully and load for full pressure or neck size and load for reduce pressure.

My problem is I have 6 Colts chambered in 45 Colt so I have to fully resize to fit in either of these guns so I have to keep pressures up. If you only are reloading for one gun then you can get away with 1/2 resizing only.

geargnasher
07-20-2010, 09:44 PM
Ed, like smkummer, I load for a fleet of .45 Colts ranging from Open Top revolvers to rifles, with Rugers at the high end. I have tried 13 different boolit styles and seven different powders to date with the goal of ONE size fits all with good accuracy, and have succeeded using 250-ish grain boolits and Hodgdon's HS6.

The .45 Colt has huge dimensionality issues, even the chambers between manufacturers have huge variances. Lee carbide sizers squeeze the brass back to proper specs, but those specs leave a really loose chamber fit. If you're sizing for one or two guns, do what has been mentioned and just segregate and NECK SIZE the brass. Recheck your slug dimensions, and check each cylinder throat separately, and also slug the barrel up to , but not through the forcing cone. You might have a restriction there that masks true groove size. If you're checking your bore slugs for possible cylinder machine work and you're doing your measuring with 6" calipers you are wasting your time, get a REAL C-clamp, 0-1" micrometer from a reputable manufacturer (Fowler, Brown and Sharpe, Mitutoyo (sp?) etc. ) before committing to cylinder specs. If your dimensions still turn out .453" groove and .451 cylinder throat, you might want to get a non-carbide sizer die and hone it out a bit so you can load full .454" boolits AFTER YOU GET YOUR CYLINDER REAMED TO .4535". You might have to get an expander plug from a 45/70 die set and turn it down to .4525" or so to complete the set.

After you get all that sorted out, try between 9.3 and 10.0 grains of HS6 with 250-grain boolits for decent 750-800 fps loads that are easy on the gun, the brass and shooter, hard on targets, and don't require much crimp to keep seated either in a cylinder or in a mag tube.

Based on experience, even with full-length sized brass, the cases start cleaning up around 9.5 grains, but of course your milage may vary. Data is courtesy of Hodgdon, Lyman #49 and Cast #3, and lots of experience. Please verify the start loads, pressures, and velocities for yourself so you can see the trend in pressure/velocity for yourself while comparing to other powders.

IMO Trail Boss is about useless because it spikes pressures bigtime right when it lights, then peters out to nothing after the boolit exits the brass. I've seen data for the .45 Colt where the peak average pressure was over 13,000 cup but the muzzle velocity was only 600 fps! If you know even a little bit about internal ballistics you can see how cruddy that is, no wonder you're getting sooty cases.

And Rockyraab, Titegroup IS position-sensitive, but less so than other fast-burning powders. I've used it quite a bit in the .45 Colt but it was never quite as accurate as some others I've used. You can definetely tell it's quick by the sharp recoil and low POI with a revolver.

Gear

Ed Gallop
07-21-2010, 07:08 AM
You didn't yank my chain smatazz Rocky. Sure, I prefer to produce perfect shiny cartridges but, like you, I much prefer perfect shooting guns. I'm retired, living a good slow life in the country, and shoot alone in my back yard (field) a couple times a week to have something to reload. Other than occasional family and friends visiting, I'm the only one looking at 90% of my cartridges and targets. They could care less.

I have learned a lot from this post and have a lot of interesting projects that will get my 45 Colt behaving like it should. Thanks a bunch. Ed.

44man
07-21-2010, 09:01 AM
All of my heavy hunting loads in the .44, .45 and .475 using heavy boolits still leave deposits on the brass. A lot of lube on some brass. Even after a day in the tumbler, a few cases need the lube scratched off with a finger nail.
Now my 45-70 BFR does not do that. Cases fall out clean, so clean a tumbler is not needed. I use 4759 and pressures are not high yet I never seen such clean brass. It can be sized right out of the gun.

freighthauler
07-21-2010, 09:54 AM
are dirty, blackend cases, guns, and fingers, really a problem???i contend with all three, happily! aren't these just, part of the good-life? happy and good shooting(and cleaning!)

geargnasher
07-21-2010, 04:09 PM
When your accuracy starts going to pot because of that dirty buildup accumulating in your cylinder throats from fresh rounds shoving that chamber filth forward, you might take an interest in tuning your loads to prevent that. Some folks shoot 2-300 rounds in a match without cleaning, and if you have a tight gun this may even make for chambering problems after a few cylinders.

As far a clean and shiny for clean's sake, I don't go overboard with that, either. When I get range pickup or dirty brass, it gets boiled in citric acid solution, dried, tumbled, dunked in warm, clean citric acid solution again to passivate it (a recent addition to the process thanks to a thread here), dried again, sorted and qc'd, then loaded and after that, I rarely have to mess with cleaning it again. It gets a kind of burnished patina that is resistent to further corrosion.

Gear

freighthauler
07-21-2010, 06:44 PM
understood,thank you,i do load onlyclean,shiny brass,and shoot clean guns,i just wondered if the blowback actually hurts anything. i shoot soft lead,soft lube,and light charges. after shooting i have lots of greasy,sooty,black mess to clean! everything performs well, so, does it hurt anything? as velocity doesn't concern me,the escaped gases don't either. OR is there danger of cutting or something? just wondering. thank you.

Johnnycoal
07-22-2010, 11:21 AM
I didn't see that anyone answered your question about the cowboy dies, so here goes.

.477 at the base
.470 mid-case
.470 up top

So pretty much the same as your Lee dies.

geargnasher
07-22-2010, 03:30 PM
understood,thank you,i do load onlyclean,shiny brass,and shoot clean guns,i just wondered if the blowback actually hurts anything. Like I said, it mostl likely only hurts accuracy and loading speed. Excessively dirty chamber/throat areas could lead to high chamber pressures in some cases, but that would have to be extreme. i shoot soft lead,soft lube,and light charges. after shooting i have lots of greasy,sooty,black mess to clean! If my revolvers have a nice greasy feel to them after shooting I know everything is going as it should, and ain't nuttin' gonna rust before I get home!everything performs well, so, does it hurt anything? as velocity doesn't concern me,the escaped gases don't either. OR is there danger of cutting or something? No. just wondering. thank you.


When I first got my Uberti 1872 Open Top in .45 Colt, I noticed several things about the brass. For one, the chambers are much tighter than any other .45 Colt I have, which is wonderful because they are exactly the size the SHOULD be, not the SAAMI cavern standard. The other thing I noticed was the primers. Using basically a starting load that works extremely well in all my other guns, I was getting one VERY flat primer in one chamber every cylinder full. I marked it, and sure enough, same one. Also had chambering issues with that hole after two cylinders. I quit shooting it until I was able to measure the cylinder throats and chambers, found that one throat .002" undersized, and it had accumulated an awful ring of carbon up to the case mouth! If you saw the case you would think it had been fired in a SBH with 24 grains of 296. Amazing what just a little restriction around the crimp will do.

Gear

freighthauler
07-22-2010, 03:58 PM
thanks gear, i'm also shooting o.t.'s, and ruger's. i do have the build-up in all my cylinders,just been scrubbing with hoppes and a bronze brush,the ring is still visible,but i don't think it is built-up after scrubbing.at any rate,they still shoot well.am using lee's 200gr.r.f. and 3.0gr. bullseye,and s.p.g. great for paper and steel @25ft.,in the garage!i do occasionally roll some fine wet/dry paper and polish(?) the cylinders. thanks to all,this site is great!

Ed Gallop
07-22-2010, 06:34 PM
Thank you Johnnycoal. That is what I was looking for. Ed.

Grapeshot
07-24-2010, 08:40 AM
I've shot and loaded for the .45 Colt since 1973. I also had a fleet of .45 Revolvers from COLT's SAA, Anaconda and New Service, S&W M25-5, Reproduction Remington 1875, SAA Clones and Uberti's Schofields.

They all ejected smokey brass until I started using 2400 in the M25-5 as well as the Anaconda. Not wanting to use my hunting loads in the SAA's or Schofield I lived with the dirty brass and dropped it in my tumbler with a cap full of Hoppe's #9. This cut the crud and within 6 hours they were bright and clean.

You can always anneal the cases, THE CHOICE IS YOURS.

I also switched to Black Powder and a 250 grain bullet for all the 19th century designs. Hot soappy water take care of the crud and when dry, back in the tumbler with crushed walnut hulls.

Ed Gallop
08-10-2010, 09:38 AM
RESULTS: This became an interesting project. After trying every possible solution with varying degrees of improvement I found annealing the brass eliminated most all blowback. If I heated not quite to the bright red glow there was little to no brass discoloring after cleaning, and there was no blowback. The brass cleaned brightly within a short time in a vibrator.

If I size brass with the Lee sizing die the brass is almost totally blackened and takes forever to clean and polish. New unsized brass and fired unsized brass only resulted in moderate to heavy smoking. Faster powder and the tightest crimp was an improvement but not by much. It was interesting that .452 cast was a bit better than .454 but the velocity loss was enormous. That was no surprise. When I fired the annealed brass with .454 I was very surprised that there was no blowback residue. I then annealed to be sure the red didn't become bright and not only did it perform as well, but the brass was not discolored.

Thanks to all for your help. Hopefully this post will help others with a Heritage Rough Rider .45 Colt having the same problem.