Reddot, .45acp, 230grn LRN, Flattened Primers...

Have you done a plunk test? Double checked length? Looks more like a spike from rifling contact by the bullet to me! Some barrels have shorter chambers and seat differently.
 
I have chosen my OAL by doing the drop test. I do believe I may have been spiking pressures by having the bullet contact the rifling, as I didn't leave much room to play around with. 1.260" OAL will generally not chamber into battery and will result in having my to thumb the slide. I discovered this when developing my loads for HS-6. I had to reduce the OAL to 1.250" to have 100% reliable chambering. I removed the barrel and performed the drop test. 1.250" passed, but with the faster Red Dot powder I probably need to rework load development with 1.230".

I am running a stock PT1911 "factory match grade" barrel. The frame and slide are also Taurus, but all internals replaced with quality parts. Master gunsmith for Kimber also tuned my trigger to a crisp 3 1/4 #. Despite the bad rap the PT1911 may have received (and by all means, I am no fan of the finish or factory trigger / parts) the frame to slide fit is tight, and picking up a used one years ago on the cheap and putting in some custom work to it, I have no doubt will shoot circles around guns 2-3x as much.
 
45acp "factory match grade" barrel.

Just my thoughts above, something to try. I read online that a shorter OAL may raise pressure, be careful. SAAMI does show Standard & Match listings for the 45acp. Could it be that a tight match grade barrel will produce more pressure than a sloppy GI type barrel? http://www.saami.org/specifications_and_information/index.cfm?page=CC For 50 yds slow fire, i seat to just touch the rifling with 3.8gr Bullseye & 200gr lswc. A light target loading. Timed & rapid fire rounds get a shorter OAL. Click photo for larger.
th_45acp947inch_001.jpg
[/URL][/IMG] Let us know if you find the reason why the primers look that way.
 
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I had to reduce the OAL to 1.250" to have 100% reliable chambering. I removed the barrel and performed the drop test. 1.250" passed, but with the faster Red Dot powder I probably need to rework load development with 1.230".
Your max load is 5.1gr and your minimum OAL is 1.126" so if you start back at 4.5gr you will be fine as far as pressure and OAL. 4.59gr would be your start load at a 10% reduction from max charge of 5.1gr i believe.
 
Going to be working this issue my self. Down to my last 1/4 can of Bullseye.
Havent seen that in over a year.

But I have 4 pounds of Red Dot and a few weeks ago I scored 8 pounds of Promo.
So I guess i get to find a new load.
 
But I have 4 pounds of Red Dot and a few weeks ago I scored 8 pounds of Promo.
So I guess i get to find a new load.
I recon you mean 45 at least but if your loading any 9mm the only listed data is in manuals or on Alliant's older data publications. I love it in my 9mm's. I can get 1700+ rounds of 9mm per lb too and with the shortage of pistol powder I won't need any for a bit.
 
I recon you mean 45 at least but if your loading any 9mm the only listed data is in manuals or on Alliant's older data publications. I love it in my 9mm's. I can get 1700+ rounds of 9mm per lb too and with the shortage of pistol powder I won't need any for a bit.

Yes, I had not even touched my powder measure I use for my 45acp loads.
Never ever would have thought Bullseye would be a cant find item.
I used RedDot primarily as a cast bullet pusher in 308 win bolt gun.
Getting to learn new uses now.

The one powder though that is going to cause me to go into convulsions when i run out, is 2400.
Down to my last 1/2 pound of that. I have not seen a can of that for well over 2 years.
 
Confused.

I've loaded and shot 3000 rounds of 4.6/Promo/225gr. Lee Truncated Cone through my 1911, several Glocks, a SiG, a S&W 1955 revolver and a S&W M1917 revolver, with no hint of pressure problems. I still use this load for IDPA and other competition, and just general purpose shooting. If 4.0/RedDot/230 LRN is an over-pressure load, then 4.6/Promo/225 must certainly be, only more so. Since 85 - 90% of that 2000 rounds was digested by one pistol, my SA National Match 1911A1, I SHOULD have blown up SOMETHING, by now.

I had funny-looking primers, redolent of what the OP described @ 4.0/ RedDot/230, which abated (for me) at 4.3 or 4.4/Promo. I suspect the OP was right, concluding the "flattened" primers were from the aberrant motion of the primer vs. the case, encountered from chamber pressures BELOW the optimal operating pressure band of the cartridge. Just because it happens most often in revolvers, does not preclude its occurrence in autos.

ALLIANT POWDER lists (listed) 4.0/RedDot/230L as a starting load, launching the projectile at 810 f/s from a 5"barrel. The same data batch lists 5.0/Red Dot/230FMC as a max load, with a muzzle velocity of 910 f/s. There was no +P listing for .45 A.C.P. by Alliant at the time, so I conclude that these loads were somewhat short of SAAMI Max Average pressures, or Alliant is more daring than their attorneys know.
 
I will experiment with various loads from min to max, at varying OALs and post my results here in the future.

It was brought to my attention that what I am seeing MAY be caused by low pressure. I must proceed with this cautiously. My initial thoughts were I most likely was not having a low pressure condition because all the rounds had enough power to cycle the action, cases were not sooty, etc. Nonetheless the idea of low pressure made me open my reloading manual to look at pressures.

According to lee, it lists Red Dot 4.0 min to 4.0 Max @ 810 ft/sec with a pressure of 12,800 PSI when seated at OAL 1.190.

12,800 is relatively low, considering the max pressure for the 45 ACP is 21,000 PSI and 23,000 PSI for +P.

Considering I increased my OAL to 1.250", or .06" longer than the min OAL the book calls for, I must have lowered that 12,800 PSI pressure. The Question is, and I suppose this goes for any cartridge out there for any powder load, how much more powder can you add to make up for the decrease in pressure caused by seating to a longer OAL?
 
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Update: While sizing my brass, I found the casings showing pressure with the "cratered" primers to size effortlessly compared to any other brass I had.
 
Update: While sizing my brass, I found the casings showing pressure with the "cratered" primers to size effortlessly compared to any other brass I had.
Size effortlessly, would seem to be low pressure.
Agree.

If the pressure is to low and the case does not form to the chamber walls to hold it the case will be pushed back against the breach face. The greater the distance the harder it will hit. That will partially flatten a primer.

Add that to the carbon patterns on the cases say that the case did not seal up against the chamber wall because the pressure was too low.

Between the carbon on the cases, the lack of case expansion evident in cases when sizing, and the low charge (Below Alliant Data), I believe you've found the cause of the flattened primers.
 
Remembering.

The mention of difficult resizing made me think (can't find reloading notes), and I don't recall EVER having actually tough resizing, from 4.0 - 5.0/Promo/225-230. In the 4.7 - 5.0/Promo/225 - 230, I noticed that resizing seemed to require MORE effort on the press lever, but STILL not so much more
that it slowed my production or tired me.

When I said that I'd shot 3000 rounds of these loads, that is not an exact figure. It is an estimate of the minimum number that have been put through the weapon(s) mentioned. The actual number could be higher by as much as 10%. Just clarifying.
 
I haven't had the time to play around with newly developed loads as of yet, however, I found something interesting...

While having my 1911 apart for cleaning I decided to polish the barrel hood...(I went ahead and polished the entire barrel...the factory finish was a horrid looking oxidated aluminum type finish, now it's shinny stainless :) ) and subsequently after this I did a thorough cleaning and inspection. I noticed a slight build up of lead in the throat area. My rounds passed the plunk test, however, the LRN bullets are not seated with the bullet shoulder flush with the case. The end of the chamber definitely shaved a few of my shoulders so with this gun I know now my MAX OAL with this bullet can not exceed 1.250", and probably would experience feed issues if prolong firing at this length continued without cleaning. I will reduce my OAL slightly when working new loads.

The interesting part was flashlight time. I noticed that the 3 o'clock to 9 o'clock (bottom half) of the leade, or free bore, to appear 1/32" or slightly less, while the top - just past the chamber - there appears to be much less, or non-existent free bore. I can not make out tapering of the rifling (I assume it must be there) but after removing any and all lead build up, clearly I can see that the reaming job is not concentric. Despite this (factory match grade barrel lol) it shoots very accurately.

I wish the SWISS would manufacturer a 1911. They always knew what they were doing...
 
OLD Thread.

The primers shows pressure signs cause by a short chamber in 45 acp, 1911 type firearm. As the action opens the high primer gets primer wipe. A gun smith corrected the chamber problem with a reamer. Not sure i buy this as the cartridge headspaces on the case mouth. Not sure how it could build pressure this way as the bullet is not trapped/ crimped into the chamber like a bottle neck round in a bold action rifle. The 45acp short chamber would hold the action open a tiny amount but still fire if the disconnector was not activated. A bulge might appear near the head if pressure was high. Very Strange.
 
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