.45 Colt not quite a squib load but...

It could have been something in the brass that was missed before adding powder. A drop of moisture, a piece of pocket lint...
Double check and triple check.
I was loading some 223 last night, setting my scales. As I dumped some powder from the scales back into the powder measure, I caught a piece of fuzz falling into the measure.
Could have caused a future problem .

“No powder load” would not have driven the bullet out of the barrel.

it was either a light load or a partial ignition caused by foreign object or powder contamination or aliens.

More often than not, a squib from no powder will lodge a bullet in the barrel. Your powder charge is near the bottom so my guess would be a faux pas and a light load (I found dipper charges can vary by a full grain +/- depending on method). I used dippers for years but usually checked my dipping method with a scale. Early in my reloading I weighed every charge and now when working up a load I weigh every charge. Perhaps double check your "dipping" with a scale?

+on double checking the dipper for the weight. I run about the same load through an SAA (not Ruger) with about the same barrel length without a problem. Trailboss is a very fluffy load and it would be very easy to lose some flakes (actually more of a donut shape) if you're not real careful.

Sounds like a good mouse load if it can be duplicated.

The one squib load I have ever had didn't even get the bullet all the way into the barrel... it kept the next round from chambering because it was just jammed into the lands. That was a 220 grain bullet. There's no mineral-fracking way a no-powder, primer-only charge moved a 250 grain bullet down and out the bore. You had at least some powder in that round for sure.

Your powder charge is too low.

According to this web page:

Reloading The .45 Colt

the minimum factory load for a 200 grain bullet is 5.5 grains at 705 fps. You are below that and you are lucky not to have stuck a bullet in the barrel and fired a round after that. Your load must have been in the low 600 fps to upper 500 fps.

Jbird45 said:

Starline brass, Winchester large pistol primer, 4.8 grains (1.0cc) trail boss powder, .452 250 grain lrnfp sns casting lead boolit.

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Slamfire said:

Your powder charge is too low.

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As Slamfire said, "Your powder charge is too low."
The Lyman manual I have sitting in front of me lists a minimum load of 5.2grs of Trail Boss behind a 250 cast BULLET. You're flirting with sticking a BULLET in the barrel.
Not only that, but have you actually weighed a few of the charges you think your dipping with that "1.0cc" dipper, or are you just going by what the chart says? In my experience, those charts that come with those powder dipper sets are seldom accurate - with some powders they're close, some powders not so much.
Also as others have said, I too doubt you didn't have any powder in the CASE. I did that once. But I was lucky enough to have had a good enough crimp, and the bullet never even left the CASE. Otherwise, I would have probably blown up my gun because there would have been a bullet stuck in the barrel, and thinking I'd had a misfire, I fired another round. It wasn't until I ejected the empty CASES from my revolver that I discovered one CASE still had a BULLET in it. When I later pulled the BULLET, I discovered its base was burned black from the primer that actually did go off. But with my hearing protection, I hadn't heard it.

I shoot 250's with 5.8 grains TB and that's good for 720 fps out of a 5.5" barrel. As @Slamfire mentions, you should at least be at the starting charge for reliable ignition performance.

Slamfire said:

Your powder charge is too low.

According to this web page:

Reloading The .45 Colt

the minimum factory load for a 200 grain bullet is 5.5 grains at 705 fps. You are below that and you are lucky not to have stuck a bullet in the barrel and fired a round after that. Your load must have been in the low 600 fps to upper 500 fps.

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Look at the Hodgdon data 4.5 to 5.8 of TB

Yes it is a light load, sounds like a "scooping" error. Up the charge a bit.

Technically it still was a "squib" which is any Under-powered load.

Jbird45 said:

According to your chart you sent, trailboss with a 250 grain LRNFP starting load is 4.5 grains. I have the data from my book below as well. At 4.8 grains I should be ok

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Should be if your barrel is the same and your bullet hardness and sizing and lube is the same and your scale is the same as that used to find the data. If you’re seeing evidence of it being potentially light, use that data to revise your safe starting load. Plus scooping those giant TB donuts has proven inconsistent for me. You might weigh a few and see how accurate you’ve been scooping. IME scoop charts favor to the light side.

The OP’s load is slightly above the Hodgdon starting load, that velocity is just over 600 fps in a 7.5” barrel. That is very slow, so a poor crimp, a light scoop, weak brass, different lot of powder - almost anything could have caused the squib. Like others have recommended, increase the charge. Max is 5.8 grains, still a very light losd at 727 fps.


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Jbird45 said:

I use a single stage press and load my casings with a Lee powder Dipper.

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Have you checked the actual weight of the powder, or are you just trusting Lee's conversion chart?

I ask because, when it comes to their volumetric powder measures, I have never seen the chart be close to correct. It has invariably been low - i.e., if I trusted the chart, the powder charge would be light every time.

Weigh your charges. Don't eyeball it, and don't count on volumetric conversion charts.

ATLDave said:

Weigh your charges. Don't eyeball it, and don't count on volumetric conversion charts.

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+1

1KPerDay said:

IME scoop charts favor to the light side.

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That's been my experience too. I have a few favorite revolver (38 Special and 45 Colt) loads, and I've found that when dipping Unique, I have to scoop deeply into the bowl of powder, heap the powder up in the dipper, and have a few flakes of powder sitting on the handle to get the amount of powder (by weight) I'm looking for.
For that matter, I have a really old Lee dipper kit. And years ago, I wrote over what it said on that sliding chart for some of my favorite powders. I wrote what the dippers actually hold (by weight) when filled level.

Is Trail Boss position sensitive? I haven’t used it but have had similar results trying to make extra light loads with position sensitive powder in 38 special.

Slamfire said:

Your powder charge is too low.

According to this web page:

Reloading The .45 Colt

the minimum factory load for a 200 grain bullet is 5.5 grains at 705 fps. You are below that and you are lucky not to have stuck a bullet in the barrel and fired a round after that. Your load must have been in the low 600 fps to upper 500 fps.

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I think you are mistaken. He wrote 250 grain. The range is 4.5 to 5.8 according to Lyman. I just tested 4.9 with 255 gr and it was fine.

Jbird45 said:

I will have to up my powder charge a bit I think. I've been getting crappy accuracy with these loads anyway.

Maybe I should try some unique too. I have heard 8.0 grains and a 250 grain LRNFP is a good cowboy load

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Indeed. And it's actually pretty stout.

1KPerDay said:

Indeed. And it's actually pretty stout.

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Cowboy is probably more like 6.5. You don't want muzzle flip when trying to shoot as fast you can.

1KPerDay said:

Indeed. And it's actually pretty stout.

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Yeah, I use 8.0 or 8.5 under a 210 grainer for .41 magnum "police" loads - it's not true magnum power, but it's beyond what you'll get with a service-caliber cartridge (9mm/40/45) in terms of thump/recoil. Add another 40 grains of bullet weight... that load is no joke.

Always heard the 250gr lswc with 8.0gr of Unique referred to as a factory .45Colt round.