Colt Delta Elite Recoil System
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BBBBill
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Better off fitting an EGW square bottom firing pin stop and running a 20# spring. Might even be able to drop it to an 18 or 19#. Don't do that without the new stop though. You will also need to keep a full power mainspring (23#) to do this.
If memory serves me...Ned Christiansen settled on a nearly square bottom on the stop...a 25-pound mainspring...and 18 for the recoil spring in his 10mm builds.
BBBBill
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Certainly help to avoid pounding the slide stop pin, bottom lugs of the barrel, and the risk of egging out the slide stop pin hole in the frame. I've seen it and it ain't pretty..... 
If I could only convince the "More spring to stop the frame destruction" crowd of that little fact, Bill.
The "recoil" spring's primary function is returning the slide. Whatever else it does is incidental.
Tuner,
You are right on the mark there. I have gotten some funny reactions when I tell people that Glock uses the same spring rate recoil spring along the lines of frame sizes. For example the Glock 17, 22, 34, 35 all use the same recoil spring. They look at me and argue....THAT CAN'T BE.. the 40 MUST have a stronger spring. NO...the spring is there to move the slide forward and load the next round.
Glock controls recoil with slide WEIGHT. If you look inside various models they are cut differently to remove mass for the light calibers. The 10mm Glock 20 has THICK slide walls to retain weight. The model 34 has a BIG window cut in the slide and metal machined out along the inner areas where the barrel sits. The slide is longer than the 17...uses the same spring....and so the slide must be lightened to equal the weight of the 17 slide.
When I convert a Delta to a single recoil spring I run a 19 or 20 pound and use a flat bottom FP stop and a 20 pound main when using 10mm loads that replicate hot 40. For full house ammo the main goes to 23 or 25 depending on load.
A person has to fool the gun into thinking the slide is very heavy. That is better done with the main spring. Running super heavy recoil springs opens a whole new can of worms.
You are right on the mark there. I have gotten some funny reactions when I tell people that Glock uses the same spring rate recoil spring along the lines of frame sizes. For example the Glock 17, 22, 34, 35 all use the same recoil spring. They look at me and argue....THAT CAN'T BE.. the 40 MUST have a stronger spring. NO...the spring is there to move the slide forward and load the next round.
Glock controls recoil with slide WEIGHT. If you look inside various models they are cut differently to remove mass for the light calibers. The 10mm Glock 20 has THICK slide walls to retain weight. The model 34 has a BIG window cut in the slide and metal machined out along the inner areas where the barrel sits. The slide is longer than the 17...uses the same spring....and so the slide must be lightened to equal the weight of the 17 slide.
When I convert a Delta to a single recoil spring I run a 19 or 20 pound and use a flat bottom FP stop and a 20 pound main when using 10mm loads that replicate hot 40. For full house ammo the main goes to 23 or 25 depending on load.
A person has to fool the gun into thinking the slide is very heavy. That is better done with the main spring. Running super heavy recoil springs opens a whole new can of worms.
Careful, Mac. You can draw a lotta flak by usin' facts in a discussion about recoil springs.
Go ahead and ask me how I know...
Go ahead and ask me how I know...
Yep...it is a lot like having discussions about ejection problems and telling them it is extractor issues. I have had a couple customers get all sorts of argumentative about that one. Good times! 
Yeah. Like the guy that just recently got his hackles raised after he said that the German MG42 fired so fast, that there were three bullets in the barrel at the same time...and after I couldn't take it any longer...I explained as gently as I could that it would be both physically and mechanically impossible for that to happen.
I thought I was gonna hafta fight the guy...
Uh....wow. His is not a simple delusion. Haha.....I love how some shooting myths and old tales get passed around.
Along the lines of guys that preach with enthusiasm that revolvers are the best defense weapon as they are much simpler and can't jam. Uhhhhhhh........ I try to avoid that argument as it normally leads to me popping the side cover off a K-frame to show them...and then showing them how I can lock up a S&W every time just by pulling the trigger. They normally look like
Along the lines of guys that preach with enthusiasm that revolvers are the best defense weapon as they are much simpler and can't jam. Uhhhhhhh........ I try to avoid that argument as it normally leads to me popping the side cover off a K-frame to show them...and then showing them how I can lock up a S&W every time just by pulling the trigger. They normally look like
OP
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Mac & Tuner, while I have both of you here, I'm gonna ask another odd question in regards to this Delta. I had the FP block break in a Colt XSE a few years back (internal metal looked porous, maybe was a MIM part), and that lead to my distrust of FP blocks in 1911s. I made an exception buying this Delta, since all Delta Elites are Series 80. So here are the questions:
Does anyone make a machined from heavy duty rod stock Colt S80 FP block?
Or, if I ditch the S80 parts, is there a preferred alternative to welding to fill the FP actuator cutouts?
Does anyone make a machined from heavy duty rod stock Colt S80 FP block?
Or, if I ditch the S80 parts, is there a preferred alternative to welding to fill the FP actuator cutouts?
BBBBill
Member
Did it show evidence of improper timing? Was the hammer dropping before the firing pin plunger had cleared the firing pin? That would show up as peening on the body of the plunger and the shoulder of the firing pin.ugaarguy said:
I've never seen one break that was not due to improper timing.
Very few folks weld the hole in the slide. Messing up the heat treat is a concern. They just leave them open.
The holes won't cause any problems. I have a Delta that I pulled the Series 80 parts out of the day I bought it. It's had over 10,000 rounds through since. It was my IPSC gun for over 10 years. All I did was round off the little actuator doohickey (I have no idea what it's called) so that it would act as a spacer for the pin. I know they now sell parts designed to do that. Never had any problems.
Got to be a timing problem. A correctly timed Series 80 system is reliable and trouble free.
In the early days, I rarely saw a timing issue with them. Nowadays, it seems like it's cropping up a lot more often.
You don't need to weld up the frame. Order a TJ's frame blank from Brownells. It fills the space left by both frame levers. Be sure to remove it and inspect it every couple thousand rounds and dress the flanging around the holes. Replace it when it needs to fourth dressing. They're only about 5 bucks, so it's probably a good idea to order 2 or 3.
In the early days, I rarely saw a timing issue with them. Nowadays, it seems like it's cropping up a lot more often.
You don't need to weld up the frame. Order a TJ's frame blank from Brownells. It fills the space left by both frame levers. Be sure to remove it and inspect it every couple thousand rounds and dress the flanging around the holes. Replace it when it needs to fourth dressing. They're only about 5 bucks, so it's probably a good idea to order 2 or 3.
OP
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Update
The Delta has been updated a bit. I have wide and really short fingers, which is why I made some of these changes.
First, I took the wraparound grips off, and put a set of standard checkered rubber grips on it, until I decide which nicer grips to install. I just can't bring myself to cut the front strap out of the pistol's original Delta medallion grips. Midway was out of the smooth, polished blue, Ed Brown flat MSH. As a temporary solution I ordered the $8 Colt grooved Delrin plastic flat MSH, which is just the flat version of the factory MSH anyway. Those changes took care of the grip length.
I shoot with a high thumbs grip too, so a beavertail grip safety was a must. The Wilson semi drop-in fitted surprisingly well, and will let me put off frame tang cutting & refinishing for a bit.
Per y'all's advice I ordered a 25lb mainspring, and put that in the flat MSH. I recycled the other small parts out of the arched MSH. I also ordered the EGW Series 80 oversize flat bottom FP stop. I've done a much better job fitting small parts in the past. I'll admit that my fitting of the new FP stop wasn't pretty, but it is functional. I ordered a Wolff 18.5lb recoil spring, and a Wolff 20lb recoil spring. I already had a standard GI short recoil spring guide. I went ahead and put the an extra power firing pin spring (Wolff is including these with their recoil springs now) in while I had the slide apart. When / If I pull the S80 parts the spring is ready for a Ti firing pin.
So, everything fitted, I took it to the range tonight with the 20lb recoil spring in it (I'll run the 18.5lb soon). Ammo was 50 rounds of Atlanta Arms & Ammo reman' 180gr JFP. The felt recoil difference & improved shooting comfort were amazing. No doubt the heavier mainspring and square bottom FP stop were the main factors. I'm sure the improved grip configuration didn't hurt either.
In short, thank you Mac & Tuner for the great guidance on 10mm 1911 setup.
The Delta has been updated a bit. I have wide and really short fingers, which is why I made some of these changes.
First, I took the wraparound grips off, and put a set of standard checkered rubber grips on it, until I decide which nicer grips to install. I just can't bring myself to cut the front strap out of the pistol's original Delta medallion grips. Midway was out of the smooth, polished blue, Ed Brown flat MSH. As a temporary solution I ordered the $8 Colt grooved Delrin plastic flat MSH, which is just the flat version of the factory MSH anyway. Those changes took care of the grip length.
I shoot with a high thumbs grip too, so a beavertail grip safety was a must. The Wilson semi drop-in fitted surprisingly well, and will let me put off frame tang cutting & refinishing for a bit.
Per y'all's advice I ordered a 25lb mainspring, and put that in the flat MSH. I recycled the other small parts out of the arched MSH. I also ordered the EGW Series 80 oversize flat bottom FP stop. I've done a much better job fitting small parts in the past. I'll admit that my fitting of the new FP stop wasn't pretty, but it is functional. I ordered a Wolff 18.5lb recoil spring, and a Wolff 20lb recoil spring. I already had a standard GI short recoil spring guide. I went ahead and put the an extra power firing pin spring (Wolff is including these with their recoil springs now) in while I had the slide apart. When / If I pull the S80 parts the spring is ready for a Ti firing pin.
So, everything fitted, I took it to the range tonight with the 20lb recoil spring in it (I'll run the 18.5lb soon). Ammo was 50 rounds of Atlanta Arms & Ammo reman' 180gr JFP. The felt recoil difference & improved shooting comfort were amazing. No doubt the heavier mainspring and square bottom FP stop were the main factors. I'm sure the improved grip configuration didn't hurt either.
In short, thank you Mac & Tuner for the great guidance on 10mm 1911 setup.
Delaying the slide a tick longer makes quite a bit of difference in how fast it compresses the spring and in how hard it hits the impact abutment...which is where most of the felt recoil comes from.
The explanation is fairly simple.
Delaying the slide at the outset of the action/reaction robs it of momentum before it gets a full head of steam. Harder to slow it down after it's moving at full speed than it is before.
It also places the bullet farther along in the barrel relative to the slide's position...which means that the bullet clears the muzzle earlier in the system's movement...which removes the accelerating force sooner...which means that the slide starts to decelerate sooner.
Little things mean a lot sometimes.
The recoil system creates an action/reaction event separate and apart from the ballistic event. The spring is the force vector. The stronger the spring, the harder it pushes forward on the slide and rearward on the frame as it compresses. The slower the spring compresses, the more time it takes for the slide to hit the abutment...and spreads the reaction out over a longer period of time.
You've just discovered a little-known part of John Browning's genius.
The explanation is fairly simple.
Delaying the slide at the outset of the action/reaction robs it of momentum before it gets a full head of steam. Harder to slow it down after it's moving at full speed than it is before.
It also places the bullet farther along in the barrel relative to the slide's position...which means that the bullet clears the muzzle earlier in the system's movement...which removes the accelerating force sooner...which means that the slide starts to decelerate sooner.
Little things mean a lot sometimes.
The recoil system creates an action/reaction event separate and apart from the ballistic event. The spring is the force vector. The stronger the spring, the harder it pushes forward on the slide and rearward on the frame as it compresses. The slower the spring compresses, the more time it takes for the slide to hit the abutment...and spreads the reaction out over a longer period of time.
You've just discovered a little-known part of John Browning's genius.
Well...no...but the "recoil" spring's primary function is returning the slide to battery...not decelerating it. That's why it's there. That it does decelerate the slide is incidental, and the result of being compressed so that it can perform its primary function...returning the slide.
You agree? That seems to contradict the other statement.
Now what? Look closely at all the things that work to fight the slide's acceleration and momentum the instant that it starts moving...is what.
One is hidden, and sometimes not readily understood.
Now what? Look closely at all the things that work to fight the slide's acceleration and momentum the instant that it starts moving...is what.
One is hidden, and sometimes not readily understood.
This is a great thread, thanks guys!
I have a Delta that I've had no real problems with but it always seemed to be "not quite right". I always took the recommendation to run these heavy recoil springs and just live with it.
I have a squared off FP stop and heavier mainspring on the way from Midway, should be here tomorrow. Your explanation makes perfect sense, wish I'd known of this years ago.
Thanks again for sharing.
I have a Delta that I've had no real problems with but it always seemed to be "not quite right". I always took the recommendation to run these heavy recoil springs and just live with it.
I have a squared off FP stop and heavier mainspring on the way from Midway, should be here tomorrow. Your explanation makes perfect sense, wish I'd known of this years ago.
Thanks again for sharing.
JERRY
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i said theres nothing to slow down the slides rearward movement except the recoil spring. is this wrong?
i also said that the slide picking up a round as it comes forward slows down the slide a little. is this wrong?
i do not know enough about 1911s to have them as part of my screen name so i yield to the moderator from north kackalaki.
i also said that the slide picking up a round as it comes forward slows down the slide a little. is this wrong?
i do not know enough about 1911s to have them as part of my screen name so i yield to the moderator from north kackalaki.
Everything that has the opportunity to delay or decelerate the slide will do just that. Known as "Outside Forces" as per Newton 1B. To wit: An object in motion will remain in motion unless and until it encounters an outside force. Nothing is everything, but everything is something.
The mainspring is part of it. The slide cocks the hammer, and the mainspring powers the hammer...so the mainspring and the hammer's inertial mass fight the slide's acceleration.
The recoil/action spring is a part of it, of course...but that's not why it's there. The gun can be fired without a recoil spring, and about all that will change is that the shooter will have to manually push the slide back to battery. If you want to test this, I suggest using a full-length guide rod. A standard "stub" guide rod will get cattywampus and crash the gun.
The main delaying force acting against the slide is the passage of the bullet through the barrel...pulling forward on the barrel via friction while the slide drags it backward. This robs the slide of more speed and momentum than all other outside forces combined.
The barrel's inertial mass is fairly significant. The slide carries the barrel with it for a short distance...so that has to be factored in as well.
Rail friction also works to decelerate the slide, even though its influence is miniscule. Gravity is another outside force, small though it may be. Even a gnat that flies into the path of the moving slide represents an outside force. Everything is something.
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