Smoke in the eyes when shooting a 45 Colt Rifle: Understanding blow-by.

["Big Boston"]

A fellow shooter called the other day, wanting an opinion on the what was causing the olfaction and ocular irritation when he was shooting his 1894 Marlin in 45 Colt.

 

The exact complaint being that the last couple of shots were smelling nasty and causing his eyes to water a bit. This issue was recent, and in addition to the irritation there was an issue with the extractor gumming up and the need for frequent action cleaning. For several seasons there hadn't been any issues, with gumming up or with irritating smell or smoke. The recent change was a going from 250 grain bullets to 200 grain bullets and having cleaned the action with an aerosol spray. A quick look at the SDS sheet did reveal some irritants, but as there was also an accompanying action fouling issue, I suspected blow-by. 

 

We decided that a bit of testing was in order, and we started by taking a video. I recorded in normal mode and we ran a full magazine, making the details a bit hard to pick out. I played it several (many) times and finally picked up on the blow-by. Just as the shot is fired, I could see a plume of smoke traveling up past the peak of the shooters hat. In addition, after the 10 shots were fired, the gun was loaded with a single round and a piece of clean white paper was wrapped around the side of the action, and then the shot was fired. This confirmed blow-by. 

 

 

 

The piece of paper on the left is with the shooters 200 grain ammunition and on the right is a shot fired with my 45 Colt 250 grain ammunition. 

 

We still have a bit more testing to do, and I'll take the video in slow motion this time, against a dark(ish) background, and certainly repeat the paper test as well. 

 

Blow-by and mitigating the occurrence of blow-by has been discussed in this forum, I'll not go into that. This was a fairly extreme case, and measuring cases showed a real absence of any case expansion. The shooters brass was assorted range brass and it also revealed that some brass is stronger than other brands. It also became apparent that it's pretty hard to build pressure fast enough to expand the case with a light bullet.

 

Thanks for reading my post to the end, I did want to pass on the paper test for checking blow-by, and the hint to film in slow motion. 

 

BB

[Garrison Joe, SASS #60708]

I've chamber cast some Marlin 1894s made in .45 Colt, and found oversized chambers.  The SAAMI specs are very generously sized already, because this is a very old cartridge with lots of ancient precedent of chamber size.  But on top of that, the chamber was reamed another 3 to 5 thousandths larger than the max (which is 0.4862" at the base end datum, and 0.4806" at the mouth).    Combine that with the very thick cartridge case walls typically used, which will not expand with typical .45 Colt chamber pressures, and blow-by is a common problem with these pistol-caliber rifles, regardless of the maker.  Cowboy loads with light charges and light bullets make this problem even worse.

 

Yes, visual monitoring of the gas squirting up from the barrel breech / bolt junction is excellent proof of blow-by.  Can usually be seen with eyeball when standing to one side of shooter.   A video of it - even better and makes a record, too.

 

good luck, GJ

[Warden Callaway]

I shot a Marlin 1894 in 45 Colt for several year.  Tried a lot of things to reduce blowby.  Finally moved on to 44WCF and other calibers. 

 

 

[Abilene, SASS # 27489]

Marlins and Lightnings are very prone to that.  Toggle-link guns don't get it in your face, although they will still get dirty.

[Assassin]

Try some .454 diameter bullets. Or, some unsized straight out of the caster, just pan lube them.

[H. K. Uriah, SASS #74619]

Well, I don't get anything in my eyes, the big eyeglasses pretty much prevent that.   But I do get blowback.  I can feel it on my cheeks, sometimes, and see it on my cases.   But I only get it with .45 Colt.  I don't get it with .44-40.   The very thin case walls of the .44 seal the chamber much better than the .45 does.  And yes, I use 200 grain bullets with both cartridge.

The blowback is not really all that annoying.  I usually don't notice it, and it is much more significant on my Lightning than my 92.  Doesn't seem to be an issue with my 66 or my Burgess.   I've noticed with the Lightning that it will cause a buildup of gunk in the firing pin channel, so I always flush that out with Gunscrubber after every match to prevent failure to fire problems.  

That's my experience.

[Eyesa Horg]

When my Marlin is clean, I can feel powder hit my cheek! After a stage or two it's not so bad. Using Clays, I upped the load to 5.2gr. with a 200gr bullet and it is mo better! Trail Boss was the worst! Haven't tried 250's yet or annealing as advised. Annealing was the answer with real BP however.

[Garrison Joe, SASS #60708]

1 hour ago, Abilene, SASS # 27489 said:

Toggle-link guns don't get it in your face

 

Well, I've got a couple that do spray gas and dirt back in your face.  So, I size my .45 Colt cases with a dual-sizing ring Redding die.   It tightens the mouth but does minimal sizing on the lower 2/3 of the case.   Thus, it fills the chamber a lot better and I can run 200 grain bullets sized .452 without the blow-back.

 

That same sizing die solves a Marlin 1894 gas blow-by problems for a couple of shooters that I recommended to.

 

good luck, GJ 

["Big Boston"]

33 minutes ago, Assassin said:

Try some .454 diameter bullets. Or, some unsized straight out of the caster, just pan lube them.

 

Interesting. I'd considered casting some softer, like bhn 10 or so, to see if that increased pressure, hadn't though about larger. So large and soft or large and hard? No sexual innuendos intended. 

 

BB 

["Big Boston"]

7 minutes ago, Garrison Joe, SASS #60708 said:

 

Well, I've got a couple that do spray gas and dirt back in your face.  So, I size my .45 Colt cases with a dual-sizing ring Redding die.   It tightens the mouth but does minimal sizing on the lower 2/3 of the case.   Thus, it fills the chamber a lot better and I can run 200 grain bullets sized .452 without the blow-back.

 

That same sizing die solves a Marlin 1894 gas blow-by problems for a couple of shooters that I recommended to.

 

good luck, GJ 

 

I use the Redding Dual carbide die for my loads, and a 250 gr bullet. We did try sizing with my die, and 200 gr bullets, but with the loads we were using, the pressures were still too low. I'd like to create pressure without increasing velocity unduly. It is encouraging that you could make it work, would you mind sharing your recipe. The bullet we used was a commercial, probably a Magma mold. Trail Boss was the powder, up to 6.5 grains. I did not chronograph the loads. A 250 gr bullet works, the shooter is trying to source some of those. COVID economics put all the close by casters out of business, and our go to supplier passed away. 

[Garrison Joe, SASS #60708]

I have no problems getting sealing with that dual-sizing ring sizer die with 6.0 grains of WST under a 200 grain Accurate 45-200E TC mold, making 8 BNH bullets. 

 

Quote

bullet we used was a commercial,

 

Commercial casters use 12 to 16 BNH alloy usually.  Sounds like you have been using alloy hard enough that cowboy velocity and pressure loads won't make bullets seal the bore well, which also means pressure can't build up enough to seal the brass against the chamber wall.   8 or 9 BNH is all the hardness needed for cowboy loads.  But for that soft a bullet you may have to cast your own, or see Desperado bullets in Oregon.

 

If a 250 grain bullet solves the problems, you are close.   Annealing the cases would probably fix the problem, too.

 

good luck, GJ

[Stump Water]

And we know why 1873s, 1892s, etc. were chambered in .44WCF.  

[Matthew Duncan]

“…The recent change was a going from 250 grain bullets to 200 grain bullets…”

 

That is the problem.  Go back to 250 grain..

[Warden Callaway]

 

[Colorado Coffinmaker]

Well, I actually  understand your not wanting to go into previous discussions of Blow-By with 45 Colt, since you went to all that trouble.  I could have inswered your question without all the fall-da-rall.  

 

To begin, the 45 Colt case, regardless of manufacture, does NOT expand sufficiently to seal the chamber against gun gas.  PERIOD!  Bigger Bullets, Softer Bullets, Heavier Loads et all do NOT eliminate Blow-By in 45 Colt.  Some extreme measures of this nature may slightly mitigate the Blow-By but WILL NOT eliminate it.  Additionally, the gun makers are want to cut 45 Colt chambers at the extream end of SAAMI or out right oversize  

 

There are TWO solutions.  First up is to start with 44-40 cases, expanded to .45 and fire formed to 45 Colt.  The afficinadoes of the 44WCF will cringe at this practice, but with the thinner case mouth of the case it works quite well.  Next up is to anneal 45 Colt cases to soften the brass sufficiently to expand.  Annealing works regardless of bullet weight or load level.  Some annealed cases may seem a little "sticky" to extract.  Annealing however, will ELIMINATE Blow-By.

[Garrison Joe, SASS #60708]

4 hours ago, "Big Boston" said:

A 250 gr bullet works, the shooter is trying to source some of those.

 

Here's a fine 250 grain soft alloy bullet:

 

https://cowboybullets.com/45-cal-250-grain_p_26.html

 

Only difficulty might be getting them to ship to your location.

 

good luck, GJ

[The Original Lumpy Gritz]

What's the load details? 

Sounds like they are to 'lite' on powder.

[Tequila Shooter]

1 hour ago, Colorado Coffinmaker said:

Well, I actually  understand your not wanting to go into previous discussions of Blow-By with 45 Colt, since you went to all that trouble.  I could have inswered your question without all the fall-da-rall.  

 

To begin, the 45 Colt case, regardless of manufacture, does NOT expand sufficiently to seal the chamber against gun gas.  PERIOD!  Bigger Bullets, Softer Bullets, Heavier Loads et all do NOT eliminate Blow-By in 45 Colt.  Some extreme measures of this nature may slightly mitigate the Blow-By but WILL NOT eliminate it.  Additionally, the gun makers are want to cut 45 Colt chambers at the extream end of SAAMI or out right oversize  

 

There are TWO solutions.  First up is to start with 44-40 cases, expanded to .45 and fire formed to 45 Colt.  The afficinadoes of the 44WCF will cringe at this practice, but with the thinner case mouth of the case it works quite well.  Next up is to anneal 45 Colt cases to soften the brass sufficiently to expand.  Annealing works regardless of bullet weight or load level.  Some annealed cases may seem a little "sticky" to extract.  Annealing however, will ELIMINATE Blow-By.

 

CC has the right answer here.  The .45C don’t expand because the case wall is thick, by annealing you soften the brass so it can expand.  The following is for newer shooters that may not know.  

 

Brass unlike steel is work hardened, meaning every time you size, bell, crimp the case it gets a little more brittle which is why you’ll see more split cases than say .38 brass.  In a bottle neck case such as .44-40 the case wall where the bullet is seated is thinner than the lower case wall.  This allows the case mouth to expand sufficiently to prevent most blow back.  That’s not to say that a bottle neck case wouldn’t benefit from annealing.  Most competitive long range CF shooters also will anneal their cases, it helps to maintain uniform neck tension.  I’ve been annealing my .45C for years and get very few split cases and even with shooting BP after a full year the action on both my ‘73 and Marlin ‘94 show no sign of blowback.  One word of caution, I’ve never experienced cases that were hard to extract in a rifle, but in a revolver the cases will expand enough that expended cases won’t fall out of the chamber, you have to use the extraction rod, but they won’t be stuck. 

[Garrison Joe, SASS #60708]

28 minutes ago, Tequila Shooter said:

Brass unlike steel is work hardened,

No, both brass AND steel work harden.   Bend a steel wire or can lid several times, it gets hard and then fatigue breaks.   The bending creates many extremely small cracks in the crystal structure of both of those metals.  Initially those small cracks just add to hardness of the metal.  But with enough bending, the cracks join together and the metal breaks at the stress fracture point.

 

Brass can be re-softened (annealed) at a much cooler temperature than steel, though.  That is what case annealing does - it allows the minor cracks to heal up and join back into normal crystals.  Thus the brass is soft again and ready for more work deformation before it breaks.

 

Limit annealing on a bottle neck case to JUST the neck, though.  If you soften the shoulder, the case will collapse with very little neck tension against the bullet during seating.

 

good luck, GJ

[Tequila Shooter]

7 hours ago, Garrison Joe, SASS #60708 said:

No, both brass AND steel work harden.   Bend a steel wire or can lid several times, it gets hard and then fatigue breaks.   The bending creates many extremely small cracks in the crystal structure of both of those metals.  Initially those small cracks just add to hardness of the metal.  But with enough bending, the cracks join together and the metal breaks at the stress fracture point.

 

Brass can be re-softened (annealed) at a much cooler temperature than steel, though.  That is what case annealing does - it allows the minor cracks to heal up and join back into normal crystals.  Thus the brass is soft again and ready for more work deformation before it breaks.

 

Limit annealing on a bottle neck case to JUST the neck, though.  If you soften the shoulder, the case will collapse with very little neck tension against the bullet during seating.

 

good luck, GJ

 

Joe you are correct, I stand corrected. 

["Big Boston"]

My post was more about the testing for blow-by, although hints or tips on mitigating it are certainly welcome. 

 

On those lines I was wondering on what effect the bullet lube has on pressure. One of the nuances that I noticed about the 200 grain bullets was that the lube was getting hard, or was always hard, and on a fairly large percentage, the lube had gaps. It's been my experience that in a rifle, leading is not usually an issue. Many times a load that works fine in a rifle is less than ideal in my handgun. Size, alloy and lube have a larger variance zone and still have acceptable performance. 

 

I'd also like to add, that I load with a Redding Dual Carbide Ring FL die, with a 255 grain bullet, at 850 fps in a rifle and 730 fps in a handgun, with Starline brass and blow-by has been mitigated to acceptable levels. I'm happy with the ammo. It also shoots fairly close to the sights in my guns. What puzzles me is how much different a 200 gr bullet behaves. I'd tried 200 gr bullets in Schofield chambered revolvers, and they shot so far off the sights I abandoned them early on, and never bothered loading them in the 45 Colt. 200s didn't seem to work all that well in the 44 mag, compared to a heavier bullet, and even in the 44-40, a slightly heavier bullet works nicer. I have a 427666 mold that drops 213 - 216 gr bullets and they shoot nicer than the LEE 429-200 that drops 204 -206. Bullet shape is a bit different, that may be more of a factor than weight. I just use the 42766 and moved on. 

 

Certainly on the lower end of the working pressure, some brass expands easier and more than some other brass. In my 38 Spl, I have a batch of old W-W nickel plated brass from wadcutter ammo that expands superbly. IMHO, having thinner brass just up from the web gains more than in sealing than the mouth in a straight walled case. In the shouldered cases like the 44-40, the shoulder seals first IMO. 

 

I'm still in the theory part of this project. I'm trying to visualize, or understand the pressure vs time vs the position of the bullet. I'm thinking that as the bullet leaves the case, case expansion ceases. I'm like Homer Simpson, thinking hurts my brain, I prefer it when a load works out of the gate, and doesn't need to be fixed. 

 

BB

[Lucky R. K.]

A 250 grain lead bullet and a hot smokeless load or a full case of black powder should solve your problem. It did for me many years ago.

Lucky 

[Garrison Joe, SASS #60708]

One thing I learned a LONG time ago - never think two different guns will shoot the same lead cast bullet to the same accuracy.  I have no problem with 200 and even 175 grain slugs' accuracy in .45 Colt guns, which are most of what I have for Cowboy shooting.  Lead bullets seem to have a mind of their own about how well they want to shoot.  I have quit arguing with them - they are "too hard headed"  - and just listen to what each gun tries to tell me. 

 

I will say that when shooting 100 yard "long range" matches, I throw in some loads with 230 grain slugs and more velocity than my usual match loads.

 

good luck, GJ

[ORNERY OAF]

See , the good Lord is telling people to shoot big bullets(200g is not big,fyi) with lots of powder.     Mousefart shooters, you have been warned!

[Scarlett]

On 10/29/2023 at 2:03 PM, Assassin said:

Try some .454 diameter bullets. Or, some unsized straight out of the caster, just pan lube them.

I offer .454 sized bullets in 200gr lubed or coated for just this purpose. Sure, a heavier bullet might help… at a pretty significant increase in price.

 

Hugs! 
 

Scarlett

 

[Assassin]

2 minutes ago, Scarlett said:

I offer .454 sized bullets in 200gr lubed or coated for just this purpose. Sure, a heavier bullet might help… at a pretty significant increase in price.

 

Hugs! 
 

Scarlett

 

Marlin 38-55 chambers were really large.

They measured .379, unsized were .380 and worked perfectly. I sold a bunch of Oregon Trail bullets at WR for several years back when they were the badge sponsor.

[Griff]

If you think blowby using smokeless is bad, I've shot 45 Colt with BP in my rifles since 1987 when I bought my first 1873 Sporting Rifle.  Blowby is a significant problem.  I've used charges as low as 28 grains of 2F and have since settled on about 30-32 grains.  Using either a 200 grain RFN or a 225 grain TC pill cast in an RCBS 45-225-CAS mold.  At one time I used to cut out a wad from a waxed card milk carton behind the bullet.  I've found that at CAS distances, this is a needless step.  I don't use fillers.  I lube with SPG;  I've also used as light as a 160 RFN, but found the 200 or 225 grain take up enough space that they're not necessary.  I can shoot a 3 day 12 stage match without cleaning or otherwise fiddling with my rifle.  I now mostly use a Taylor's 18-½" half rnd/oct short rifle or an 1860, all by Uberti.  I clearance all my carriers so fouling doesn't interfere with its operation.  Annealing the cases is by far the biggest aid to minimize the blowby.  I splurged and bought an automatic annealer, with their "short case" adapter.  It leaves a bit more than ¼" of the case exposed to the flame.  Simple and easy to set up and operate.  I tried setting cases up in a deep cookie pan and covering the rim and part of the case with water then using a propane torch to heat the mouth... probably just as quick at the auto annealer, but, too fiddly for my attention span.  I can set the auto machine up and perform other work in the reloading shop while it churns out enough cases for me to then load several hundred at a time.  

 

Frankly, I've found that without the annealing, charge weight is a bigger factor in blow-by than either bullet weight or diameter.  Use a faster burning powder that shoots cleaner and keep your loads around 800 fps or more.  Pay attention to what powders are position sensitive and avoid them.  If you wanted to be faster, you'd have gotten a .38!  

[Burt Blade, #25657]

Winchester .45 brass seems thinnest and softest. It will eventually harden, but provides an option.

 

Also, have your gunsmith inspect headspace. And correct as needed. If excessive, blowback is aggravated. Out of battery discharges can bend things.

[Reverend P. Babcock Chase]

Howdy Anti-Blowbyers,

 

When I started out CAS with .45 Colt sixguns and rifles, I read and was concerned about this blowby deal. Naturally, I promptly forgot all about it and it never seemed to be a problem. My empty cases are dirty and the action of my 73 and 66's gets dirty, but I've never noticed blowby on my face or glasses, even with fairly light loads of 200 gr. bullets. As my fellow shooters will tell you, I'm comfortable with dirty guns as long as they continue to work correctly. I use a slightly heavier 250 gr. load in my 73 for long range and it's quite accurate so I see no need to fuss with things as, again, blowby does not seem to bother me.

 

Then again I'm a fairly insensitive critter,

 

Rev. Chase

 

 

[Cusz M. Dutch SASS Life 55326]

Try neck sizing only cases that have been fired in that rifle.  Use brass that was loaded up to the higher pressure levels in hopes that they have expanded enough to seal.

[Reverend P. Babcock Chase]

Oh yeah, I forgot to mention that I only neck size my .45's and taper crimp them. Due to the typical lighter cowboy loads many of us shoot, my neck sized, loaded rounds have a slight "wasp waist" look to them as they've never been fully blown out by higher pressures. I don't know if the foregoing does anything to diminish blowby, but as I said above, I don't seem to be bothered by it.

 

Rev. Chase

[Colorado Coffinmaker]

 

Blow-By in a Toggle Link Rifle when shooting "most" smokeless isn't much of an issue.  The carrier block just gums up until it sticks and jams the rifle.  A little squirt of Break Free and yer back in business.  The Toggle Link Carrier Block deflects the majority of the Gun Gas straight up out of the Mortice.  With Straight line actions, the Blow-By passes straight back, past the Breach Block into the shooters face.  Not so Bueno.

 

Blow-By in a Toggle Link or Straight Line Rifle with Black Powder or Subs (APP), Is another matter.  The Blow-By can foul out the chamber in just a few rounds to the point the action won't extract reliably.

 

When we speak of the Blow-By problem, we must remember, in the past, 44 Henry Flat, 44 Henry CF and 44 Stetson cartridges were Copper and sealed the chamber nicely.  Next up were the Bottle Neck rifle cartridges that seals the chamber quite nicely.  45 Colt, even in the early cartridges was never an acceptable rifle cartridge.  ALL of the big bore modern Straight Wall "pistol" cartridges, used in rifles suffer Blow-By.  Same same, it's not so much of a problem with smokeless as it is with BP and Subs.

 

Again, Heavy loads, Big Bullets and Neck Sizing will not stop the Blow-By.  Mitigate slightly - Yes.  Stop - NO.  Annealing is the answer.

["Big Boston"]

Before spending money on an annealing machine, I'd like a bit of proof. IOW, in my first post I outlined a simple "Sheet of Paper over the Action" test to quantify by comparing blow-by with a new load to blow-by of your regular load. I'd like to see the difference annealing makes. I know how much difference heavier loads, heavier bullets and neck sizing make, but so far nobody has posted any test results or any videos to show how much blow-by can be reduced by annealing. Nor have I seen any test results comparing a 451 or 452 bullet with one that is say 454. 

 

I'm thinking that my attempts to mitigate blow by have met with success because most of my brass is new from Starline. Brass age hardens in addition to work hardening. 

 

Looking forward to seeing some test result pictures posted. 

 

BB

[Colorado Coffinmaker]

Just exactly whom, suggested spending money on an "Annealing Machine??"  Annealing can be done very cheaply.  Very Cheaply indeed.  All one needs is a standard Half inch socket, an inch and half quarter twenty bolt and nut and a variable speed drill motor,  either corded or cordless, and Camping bottle of Propane with a torch head.

 

What makes you some one anyone has to "Prove" anything to.  What has been said can be easily be demonstrated for yourself if you're not too pompous to pay attention to someone besides yourself.  In fact, you haven't posted any demonstrative test results quantifying what, if any, mitigation you have accomplished.  Get over yourself.

 

Get a SASS number. you've been a "Guest" long enough

[Reverend P. Babcock Chase]

Being lazy, I don't find annealing appealing.

 

Rev. Chase