.45 ACP +P, .45 Super and .45-08 Heavy Boolit Load Data?

I had missed the extra posts since 2015 but noticed this last one. Interesting stuff.

Again, I haven't seen this fellow in a while so no updates except I maybe should have added that he told me he used to shoot approx. 15,000 rounds/year through his 1911 to stay proficient. He doesn't shoot that much anymore but that's the reason he wanted to use his 1911... familiarity and being comfortable with the gun. Of course he wouldn't have been shooting thousands or even hundreds of .45-08 rounds/per year, just load development/practice then carrying a few rounds for protection in the bush. We have lots of black bears here and now the grizzly population is getting unnervingly large.

In his case, he wouldn't likely shoot more than a very few .45-08's a year so not likely too much threat to the longevity of the gun.

I was looking forward to the load development and a good reason to get to the range. I have not been shooting much for some time due to a variety of factors but mostly too many things going on and not enough time. Got to make time!

Thanks all for the information. I have it stored away in case I ever decide to take this route.

Longbow

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Originally Posted by kingrj

As a .45 Super fan I have read reams of post regarding the requirement of a super stiff recoil spring to allow an stock .45 acp to handle the increased power of the Super..Being an engineer I just had to find out for myself so I started with conservation of momentum and calculated final slide velocity at the recoil stop for my Smith and Wesson 4506 using a 200 grain bullet at 900 fps and then at my chronographed Super load of 1230 fps. The force on the slide/barrel unit prior to unlock with the acp load is 3821 Newtons of force..With the Super load it is 7153 Newtons! By comparison the 18# recoil spring puts only 17 Newtons of resisting force on the slide/barrel unit at firing!!! The TOTAL energy absorbed by the recoil spring at full slide travel is defined by the equation KE=1/2K(x squared) where K is the spring constant and "x" is the distance in meters it is compressed. With the 18# spring the total energy absorbed during slide recoil is only 1.2 Joules as compared to the energy of the slide at lock back of 18.7 Joules!!! As you can see it doesn't matter how big a recoil spring you install on your Super...it only has a minimal effect on the final energy the slide has when it hits the end stop. By comparison the standard acp load hits the stop with 9.5 Joules of kinetic energy...So lets "change" the spring from an 18# to a 28# recoil spring and run the simulation again for the super load. This absorbs a little more energy and the final slide energy is "only" 18.0 Joules!!! You would have to put a 100# spring on these guns to get a substantial reduction in battering of the gun on recoil..So...SLIDE/BARREL MASS is the critical factor in a successful Super convertion..NOT recoil spring. Some have recommended stronger main springs and square bottom firing pin stops to 1911 guns. This is a logical and good mod and if I was converting a 1911 I would do the same but super heavy recoil springs only batter the gun on closing and force one to use high power magazine springs so the closing slide does not overstrip the cartridge. NOTHING you can do to a normal .45 acp will decrease the effect of the much higher momentum impulse of the .45 super and its resulting increased wear on the gun other than adding lots of slide/barrel mass. The only way you can make a gun "live" with the much higher pressure .45 Rolland is by fitting a heavy comp on the barrel. If anyone is interested I have made a spread sheet calculator for calculating slide velocities for any combo of bullet weights, slide weights, barrel weights, powder charges, spring rates..I have it on dropbox and can share if you want to play with it.

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Now THIS is the kind of post I really like! Your statements go directly to a question I've been researching for the last month since I decided to do a 1911 .460R conversion. I already built a .460R on a Glock 20 frame with LWD long slide, 6.61" barrel, muzzle brake, 24# recoil spring, and SS solid guide rod with the capture screw lock-tited out a few turns to correct a tendency for Glock conversions to fail to go into battery that last bit.

With the Glock conversion, there is no hammer, or hammer spring to resist slide opening so the entire system relies on the brake, and barrel friction, and even at the earliest point of unlocking, as you pointed out, the 24# spring is exerting very little closing force. The fact that I've shot several hundred rounds of Underwood .460R from the Glock without a hitch assures me the conversion is safe and quite reliable, yet it does seem the gun relies heavily on the LWD muzzle brake to delay slide unlocking, and having said that, using factory stock 10 round, single-stack mags the slide picks up the rounds reliably without added springs. Okay, so there's that....

Now we come to my real question...with the Clark .460R drop-in conversion, my first inclination is to use the 24# spring as instructed by both Clark and "the internet" yet then I read about the more effective method of using a flat bottom FPS and heavier mainspring as the primary means of resisting slide opening...and this makes sense based on my knowledge of how the Browning 1919A4 LMG works using a spring-loaded, "rocker" that is cocked as the breech mass moves rearward and as it goes forward is "tripped" to add a "kick" to force all that mass fully into closure. So basically, the use of leverage is a proven means of adding force that is far superior to a near fully extended coil spring. Come to think about it. the Beretta Tomcat also uses spring-loaded, twin levers to power the slide. So the burning question in my mind concerning the 1911 .460R conversion is...is a 24# spring really "needed" during the ignition, barrel-time, compensator offset phase of shooting? Granted the slide on a 1911 is lighter than that on a Glock, but not nearly as much as one might think....even on my long slide version the slide is about 3 ounces heavier...with LITTLE forward closing force save for the recoil spring and it should be pointed out, this force is being counteracted to some degree by the cocked striker trying to pull the slide open!
Hammer down, the act of manipulating the slide on the 1911 with 24# spring is much harder than with the Glock. So, during firing, since as you stated the extended recoil spring's "force" is quite small, this would suggest all the rearward thrust is countered by hammer leverage and mainspring pressure, combined with barrel friction "pulling" the barrel forward, combined with the compensator adding additional forward thrust as the bullet exits the barrel. On the other end, it seems rapid cycling is a major problem that causes failure to strip a round, excessive closing force that can exacerbate nose dive and bullet set-back, and possibly result in accelerated frame wear. So...based on much of what I've read about competition "comp'd" pistols, and what you so elegantly explained here, there is little practical reason to use a 24# spring. I've read some "experts" talking about using .45 ammo that makes "major" in compensated guns with recoil springs as light as 12 pounds! And these are guys who shoot thousands of rounds! This may sound insane until one considers the standard 1911 recoil spring weight is only 16 pounds...no doubt a comp will allow a lighter spring. Granted the .460R is a bit more than twice as "powerful" as generic "hardball" ammo, but if the recoil spring is really doing very little more at full closure why not drop back to the 20# for improved feeding reliability? In fact I remember reading where one guy stated that's exactly what he did and all his feeding issues went away without multi-spring magazines.

I realize I may be trying to compare apples to avocados here, but it just seems that if a hammerless Glock system with comp installed can "live" with a 24# spring, a hammer-fired, comp'd, 1911 might do better with LESS recoil spring that seems "common sense."

I know all the .45 Super aficionados talk about 28# springs, plus 25# mainsprings, and flat bottom FPS, but they aren't running compensators "Anecdotal" comments by those own .460R conversions seems to be that the guns are not heavily stressed at all thanks to the compensator.

So what's your take on all this...if any?

The 1911 can be safely fired in 45 ACP with no recoil spring in the gun at all. What does that tell you about the role of the spring in barrel unlock timing?

Consider also what is hard on the gun is pressure. Multitudinous stress risers are found in the right angles near the breechface of the slide. It is a bit silly to worry just about the frame when the slide sees increased stresses we can do nothing about.

There is a very real risk of oversprung guns outrunning 1911 magaznes as they have relatively weak
sptings. Heavy springs slow rearward slide velocity relatively little at all while they speed forward travel up quite a bit.

I won't run a heavy recoil spring in my 1911 for the exact reason you fellows just posted. I have a question. It's come to my attention that if you hold the slide on a 1911 in a safe manner and fire the pistol that the slide won't unlock or come back. I just won't try it, but what are your opinions on this?

Butt the rear of the slide against a square wood post if you are chicken. Tell us if the case comes out.

Wanna guess what happens? With standard loads slide speed is in the 15-20 mph range at peak.
FWIW.

I'd rather ask you, what happens? LOL

Assuming a 1300 fps 230 load in a standard weight uncomped 5 inch 1911 slide velocity at peak would be about 28 mph.

The case does not eject because the slide is not driven that hard.

I’ve been working this whole spiel over for many years. The single most important factor that I have found to be universal in “taming” slide velocity is the addition of a quality compensator. Used in tandem with an adequate spring, meaning attention being paid to ejection distance, and a beefy slide like the FNX T slide. I believe I have finally found the perfect marriage.

My current abomination:
FNX Tactical 45 ACP barrel
Yankee Hill Machine 3 port comp
24# Rowland RSA
+power Para 16 springs in the mags
Not responsible for anybody duplicating this load and going boom! My gun, my set up!

255 gr SWC cast in a lee mold
Sized .451
Lubed with 50/50 beeswax and crisco
11 gr of 800X
Sig brass
CCI 300 primer
COL of 1.178”
Heavy crimp with Lee FCD

That being said back down to 9 grains with the RNFP and work up.

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Originally Posted by Stuckcase

Not responsible for anybody duplicating this load and going boom! My gun, my set up!

255 gr SWC cast in a lee mold
Sized .451
Lubed with 50/50 beeswax and crisco
11 gr of 800X
Sig brass
CCI 300 primer
COL of 1.178”
Heavy crimp with Lee FCD

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Stuckcase what are you fps for that load?

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Originally Posted by akraven

Stuckcase what are you fps for that load?

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That pistol is no longer with me. It could not withstand the Rowland pressure levels. I utilize a Kimber Aegis Elite modified to accomplish the task now. A 9.5 gr 800x load behind that bullet with a Rem 9 1/2 large rifle primer yields 1282 FPS at 948 ft lbs. my two favorite loads are a Lee 230 gr TC coated with Eastwood’s light blue coating on top of 12.5 gr of Blue Dot and CcI primers and a 186 gr Lyman Devastator on top of 13 gr 800x and Rem 9 1/2 large rifle primer. It is 1530 FPS at 965 ft lbs and the 230 is 1235 FPS at 848 ft lbs. the Kimber now has over 4000 of these types of rounds through it. I use Super brass and Large Rifle primers regularly now. You can watch some of my vids on YouTube and see it in action.

Without reading through 6 pages of posts, can you tell me IF you installed a firing pin stop with a square bottom, rather than the usual rounded one? I was wondering how much it might have helped lower slide velocity. MY current project is to develop a load that will launch a 215 gr. SAECO #58 SWC at just over 1000 f/s, without going the way of the .460 Rowland or other similar rounds (though I may use .45 Super brass, for the thicker case web).

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Originally Posted by Kosh75287

Without reading through 6 pages of posts, can you tell me IF you installed a firing pin stop with a square bottom, rather than the usual rounded one? I was wondering how much it might have helped lower slide velocity. MY current project is to develop a load that will launch a 215 gr. SAECO #58 SWC at just over 1000 f/s, without going the way of the .460 Rowland or other similar rounds (though I may use .45 Super brass, for the thicker case web).

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Yes, I do. It is a hand fitted EGW. My purpose was two fold with it. One, in combination with the heavier main spring, to apply spring tension to the rearward thrust of the slide at its initial and most critical phase (if you can impede initial force you will therefore reduce slide velocity) and two, prevent extractor clocking. My MIM extractor would not make the cut and had to be changed in favor of an Ed Brown hardcore. The combination of the two with the tight hand fitting has eliminated many extraction issues.

Interesting stuff...........

This has been interesting and quite informative to me. I had a 1911 that was custom fitted and it gave me problems with extraction. I thought it was recoil spring related but never found one that worked. Now am wondering if it was simply too much friction in the fitted areas.

That also reminds me of the Colt Delta. Colt chambered for the 10mm and they used a long slide. Now I can see that they might have done it to tame the slide velocity with some extra mass in slide and barrel.

With a comp, I also wonder if you could start with a Commander length slide and a longer barrel with larger/heavier comp on it. If someone could come up with numbers I have a Commander I would not mind testing with this combo.

Colt Deltas are standard 5" slides/barrels, don't have a ramped barrel and also they didn't use a flat bottom firing pin stop...they were also known to beat themselves to death if fired with full powered loads.

I'm out of town for a while and don't have my loading data with me but am using a 240 Keith .45 AR bullet which is running at 1050+ fps and the Hornady 230 FP at 1100 fps using .45 Super cases and Longshot powder. Had the velocity of each well over that and then backed back down to the Buffalo Bore velocities.

https://www.24hourcampfire.com/ubbth...full/71573.jpg



The gun is a Kimber Stainless Target II with a 26 or 28 pound mainsping, flat bottom firing pin stop and I believe 22# mainspring. Zero issues with feeding, extraction, ejection and no pressure signs on the Starline brass.

Helped a friend build a Colt Combat Commander in .45 Super at the same time and his gun runs the loads like a well oiled machine... It has the stock non-ramped barrel.

https://www.24hourcampfire.com/ubbth...full/71570.jpg


240s at 50'

https://www.24hourcampfire.com/ubbth...full/71572.jpg


Great round...Bob

Nice guns and ammo, Bob.......

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Originally Posted by RJM52

I'm out of town for a while and don't have my loading data with me but am using a 240 Keith .45 AR bullet which is running at 1050+ fps and the Hornady 230 FP at 1100 fps using .45 Super cases and Longshot powder. Had the velocity of each well over that and then backed back down to the Buffalo Bore velocities.


Great round...Bob

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The boolit, 452423? I use that a bit. Wanting to load it to Super ballistics for a couple of my revolvers.

Kevin