Magnum Primer - 45 Auto - What's Happening??

[Hick]

I had a startling result at the range today. 45 Automatic (Argentine 1911 variant) with 211 grain cast bullet and 5.0 grains of Titegroup. I have used this load a lot with a Standard Primer and get 800 fps. Today was a first test using the same load but with a LP Magnum primer.

Anyway - with the Fed LPM primer the pistol shot well, ejection pattern of the brass was normal, and everything seemed fine. BUT, my chrono says the velocity was 2200 fps!! I figured the chrono was misbehaving so I ran some known rifle loads through it and got normal results (same velocity as in the past). Then I tested the 45 loads and again got 2200 fps. Changed the battery and again got 2200 fps! Recoil was about the same as my Ruger 357 Magnum revolver.

I got nervous - obviously - so I quit and came home and dismantled the pistol to look for any signs of overload-- but everything looks fine. Also - the fired brass looks normal and the primers look normal.

I Loaded these using a Lee dipper-- so I know they are all the same. I pulled some and verified they really are 5 grains of Titegroup. I only have Titegroup and HP-38, and the max load for HP-38 is higher than Titegroup, so I don.t think I could have used the wrong powder.

I'm trying to tell myself the problem must be the chrono but would be interested in helpful thoughts. This isn't my first rodeo-- I've loaded and fired over 80,000 rounds in various firearms and never seen anything like this.

[Finster101]

If yu have come up with a 2200 fps load for .45 acp that will shoot in a 1911 without damaging it, patent it quick! Otherwise, I would say something is amiss with the chrony setup.

[G W Wade]

Can't help with what happened but a friend had same thing happen when chronoing Bond derirnger in 9mm. Screen read 1500 fps. Your not alone. Hoping some one has a reason. GW

[376Steyr]

Well, you definitely aren't getting 2200 fps out of a 45 ACP without having some destroyed brass and magazines to go with it, so that isn't happening. I rather doubt these readings are actually related to switching to a Magnum primer. My guess is the lighting conditions were such that the big 45 bullet was casting a shadow so that the second sensor was switching off prematurely. Your smaller rifle bullets were also making shadows, but weren't big enough to detect. I don't suppose you were shooting either very early or very late in the day? Having sunlight coming from the side makes my chrono often do wacky things.

[376Steyr]

Can't help with what happened but a friend had same thing happen when chronoing Bond derirnger in 9mm. Screen read 1500 fps. Your not alone. Hoping some one has a reason. GW
Gases (muzzle blast) moving faster than the actual bullet can also trip chrono sensors and give interesting readings.

[Hick]

Well, you definitely aren't getting 2200 fps out of a 45 ACP without having some destroyed brass and magazines to go with it, so that isn't happening. I rather doubt these readings are actually related to switching to a Magnum primer. My guess is the lighting conditions were such that the big 45 bullet was casting a shadow so that the second sensor was switching off prematurely. Your smaller rifle bullets were also making shadows, but weren't big enough to detect. I don't suppose you were shooting either very early or very late in the day? Having sunlight coming from the side makes my chrono often do wacky things.

Brilliant! Morning sun low in the sky was coming from behind me at an angle so this could be it. good thinking!

[ReloaderFred]

Another question is how far from the muzzle were the screens? I place my chronograph 15' from the muzzle to keep from getting muzzle blasts messing up my readings.

The position of the sun is probably the answer to the question in this case, though.

Hope this helps.

Fred

[Tokarev]

I place my chrono 2-3 yards from the muzzle...

[cwtebay]

I don't see which chrono you are using, but I have had a similar experience with 41 RF - chrono read 1650fps yet the little Remington derringer had not exploded in my hands. Fired another string with similar results but no case or pistol damage. I determined that the chrono was picking up unfired powder being picked up at the screen. I confirmed my hypothesis by placing the screen at the muzzle, then at 15 feet.
But... if you figured out how to make a 45 ACP come out of the gun you mentioned - with no untoward issues with the gun at those velocities, PLEASE publish your data!!

Sent from my Pixel 5 using Tapatalk

[alfadan]

I don't think chronos like low angle light. They can be down right flakey sometimes.

[ioon44]

I don't think chronos like low angle light. They can be down right flakey sometimes.

That is why I went with a LabRadar chronograph, I really got fed up with the light issues.

[Der Gebirgsjager]

Just FYI -- two ammo/components shortages back, the one before the one we're just leaving, the primers were gone almost immediately, but the club I belonged to still had LP magnum in stock. The steel plate shooters used them to fuel their 1911 loads, and 3 or 4 reported cracked 1911 frames. Of course, they shoot hundreds of rounds; but still, hundreds of rounds of regular LP primers have no effect. Personally, I would avoid them in the ACP.


DG

[rockrat]

Move your chrony back another yard or two and see what the results are.

[Hick]

Range report: I went out to the range this morning early enough so that the light was at a low angle. Set up in a shady spot where the sun could only illuminate the screens, but not the sensors. Solved the problem! For what its worth: 211 grain cast, 5.0 grains of titegroup:

small pistol primers: 800 fps
Large pistol primers: 840 fps
Federal Large Magnum: 880 fps

[Hick]

Just FYI -- two ammo/components shortages back, the one before the one we're just leaving, the primers were gone almost immediately, but the club I belonged to still had LP magnum in stock. The steel plate shooters used them to fuel their 1911 loads, and 3 or 4 reported cracked 1911 frames. Of course, they shoot hundreds of rounds; but still, hundreds of rounds of regular LP primers have no effect. Personally, I would avoid them in the ACP.


DG

Magnum primers don't overload frames, hot loads do. If the load was already high, adding the pressure effect of the magnum primer makes an already hot load hotter.

[Tokarev]

My chrony likes overcast weather. In the sun, it is almost useless.

[Larry Gibson]

I'd, at least, back the load off with the magnum primers so the velocity does not exceed that of the standard LP primer.

[SSGOldfart]

I'm with Larry here, I backed off 10% then went up 2% so my loads are about the same.
on a cold morning my chrony doesn't play well late afternoon is much better btw change the battery in your chrony.

[charlie b]

Congrats on finding the chrono solution. I shoot early morning and got fed up with lighting issues. Bought a Labradar. They are not without their quirks but so much more convenient. One of those quirks is choosing between pistol and rifle. When shooting cast out of a rifle sometimes I have to choose the pistol setup to get reliable results (1500fps range). Or, I have to 'sight' the radar higher than the target due to trajectory of slower loads.

[Hick]

I'd, at least, back the load off with the magnum primers so the velocity does not exceed that of the standard LP primer.

Agreed. I did my test without backing off the LP load only because my loading manuals said I was well below max. As it is, I prefer down around 800 fps so back off is my next step.

[Kosh75287]

Try securing a large piece of butcher paper or wrapping paper at the front of the chronograph (by the rods holding up the sky screens) it MAY affect the measured velocity, but it will also detect the travel of low mass very high velocity particles through the "tunnel" (can't think of the right word) which, I believe, is the source of your 2200 f/s velocity reading. I can imagine a particle big enough to be detected by the chronograph travelling much faster than the projectile, once the projectile leaves the barrel. What I find difficult to believe is that said particle would be on a vector sufficiently parallel to that of the projectile, to overtake it and trip the chrono before the bullet. I'd expect the particle to get blasted somewhere to the side and in front of the bullet, at an angle that would send it outside the rods supporting the sky screen. Apparently something's going through there, but it beats me how.

[cwtebay]

Try securing a large piece of butcher paper or wrapping paper at the front of the chronograph (by the rods holding up the sky screens) it MAY affect the measured velocity, but it will also detect the travel of low mass very high velocity particles through the "tunnel" (can't think of the right word) which, I believe, is the source of your 2200 f/s velocity reading. I can imagine a particle big enough to be detected by the chronograph travelling much faster than the projectile, once the projectile leaves the barrel. What I find difficult to believe is that said particle would be on a vector sufficiently parallel to that of the projectile, to overtake it and trip the chrono before the bullet. I'd expect the particle to get blasted somewhere to the side and in front of the bullet, at an angle that would send it outside the rods supporting the sky screen. Apparently something's going through there, but it beats me how.That's a great idea!!
When I had the experience I mentioned above, I tried shooting to the side instead of through the chronograph and could repeat the aberrant readings. So the paper should also do the same (without as much risk of a chrony strike!)

Sent from my Pixel 5 using Tapatalk