Mainspring selection 450 SMC or 45 Super

[jeepman4804]

I hope this is in the right place, but if it isn't please just let me know. I have a Sig 1911 Extreme that I currently carry as my duty weapon. It has all Wilson Combat fire control group that Crawley Customs in Texas fitted for me. I am currently running a 17lbs Wilson Combat flat recoil spring (ISMI?) w/ GI Guide rod, 21lbs mainspring (factory Sig), and a Harrison Design firing pin stop. Currently has a consistent 3.75lbs trigger pull. My issued/carry ammo is Federal HST 230gr +P.

I already dabble a little in some heavy 45 colt loads in my Ruger Blackhawk and have been wanting to dabble a little in some heavy .45 acp loads (450 SMC or 45 Super). I have been curious about this for a while, but have started to research heavily the last couple weeks and have been unable to get a clear and concise answer on mainspring weights. I do not want to run a super heavy recoil spring for battering and general recoil impulse upon lockup, if I can avoid it.

So where should I start on mainspring weights? I was thinking about ordering a 26lbs, 28lbs, and a 34lbs from Wolff and once I figure what will work, ordering a couple three packs. I know it could increase my trigger pull slightly, but I am not too concerned with that unless it goes over 4.5lbs. I have read a lot of negatives about using shokbufs, but should I consider using them in this application (only with 450 SMC or 45 Super, not on duty)? I have also read mixed reviews of shooting 45 super in a standard non-ramped barrel. Is this a legitimate problem or is this one of those situations where you would just check spent casings for bulges in the case head? Anything else I should keep in mind?

Thanks for y'alls help,
Clay

 

[g.willikers]

Are you going to change this pistol over to be exclusively a .45 Super?

 

[Dixie Gunsmithing]

The hammer spring does nothing much for recoil (just a small amount), which is produced by heavier loads. Its purpose is to drive the hammer hard enough to set off a primer. The recoil spring is what is up-sized for a heavier recoil. However, pistol barrels are thin at the chamber, to keep them light, and the locking system, plus the chamber, are designed around a certain load. So, increasing a load will batter the lugs harder, while being locked, and increase the chamber pressure too. The heavier load may not be as much as the proof load, but the wear will certainly increase, even with a heavier recoil spring.

 

[RickB]

I have a 25# main in my dedicated .45 Super, along with a barely-beveled EGW firing pin stop, and . . . 22#(?) recoil spring.
My first set of development loads topped-out at only 970fps with a 230gr RN, and the gun was dropping the cases about four feet from the bench.
I'm hoping for over 1100fps with my next set of loads, and if the cases are going farther than ten feet, I'll probably up the rating on the recoil spring to 24#, just because it's easier than swapping mainsprings, but I think increasing the main is the better way to go.
Even the disappointing 230@970 loads showed a slight drag of the firing pin on the primer (new x-tra power firing pin spring), and I'm going to keep an eye on that. No evidence of case bulging in a standard, non-ramped 1911 barrel.

 

[jeepman4804]

To answer your question Willickers, no it is not going to be an exclusive .45 Super or 450 SMC gun. It will still need to run on my issued ammunition HST 230gr +P and be able to cycle quality FMJ with minimal changes (preferably just a running a light recoil spring). If I end up liking the Super or SMC, then I will purchase another gun to run dedicated.

I was always told the mainspring and FPS profile on a 1911 effects slide velocity exponentially more than the recoil spring. Is this not the case? I did order an extra extra strength firing pin spring, a 26lb, 30lb, and 34lb mainsprings from Wolff. Trying to get my hands on a 20lb ISMI flatspring recoil spring, but not having much luck...

 

[Dixie Gunsmithing]

The hammer spring has some effect, but as the slide travels back, leverage against the hammer from the slide increases, and the hammer spring weight drastically starts to fall. You'll fill the same thing when cocking the hammer with your thumb, in that the position of the hammer farther back takes less force to cock it.

The main effect for recoil reduction is the recoil spring, thus the heavier the spring in pounds force, the less violent the slide will recoil back. You can get the dual spring system, or add what some call a snubber, in that it acts similar to a shock absorber. The problem with adding a heavier spring, is wrenching the slide back to chamber a round and cock it.

Dual spring system:

http://www.brownells.com/handgun-parts/recoil-parts/recoil-hardware/1911-auto-recoil-master-prod16716.aspx

 

[jeepman4804]

I'm not too concerned with how hard the slide is to rack. The gun is cocked and locked 95% of the time. Only time I manually rack the slide is during dry fire exercises. How serious is the concern regarding a heavy recoil spring battering the barrel link and slide stop? Who uses the dual recoil setup and can comment in regards to reliability?

Current carry ammo is pushing 950fps according to my chrono... Hoping to push a 255gr at around 1000fps for 4 legged critters and a 230gr at around 1200fps

 

[RickB]

Heavy mainsprings allow recoil springs of more normal "1911" ratings, you shouldn't get "battering" in either direction, and the gun will have better handling qualities with a recoil spring no heavier than necessary.
Some have concerns about really heavy mainsprings resulting in damage to the hammer, or to the pin holes in the frame, but I don't know if those concerns are greater than those concerning battering of the barrel lugs, extractor, etc., associated with heavy recoil springs.

 

[Dixie Gunsmithing]

The increase of any spring will increase wear since the gun was not designed around its use. Even upping the hammer spring will cause the hammer pin hole to wear more, and the sear, over increased pressure. A stronger hammer spring can affect trigger pull too, since it increases the friction between the notch and sear.

There's not much one can do about a stronger recoil spring, and the extra pressure it applies forward. You can update the link and pin, but the lugs will still be battered slightly more in the forward direction, though not near as much as firing them will for wear. One might try to design a retarder or buffer to absorb the extra forward shock, as I don't recall anything on this being available. Everything is designed around the rearward recoil shock.

 

[RickB]

Yeah, there's no free lunch.
Moderate increases in the rating of both the mainspring and recoil spring should be a better solution than a dramatic increase in either.
Even full-power .45 Super loads are running at lower chamber pressures than 9mm, .40 S&W, or 10mm, so it shouldn't be a dramatically different problem dealing with the dynamics of the former.
I'm running essentially the same set-up in 10mm and my Super.

 

[g.willikers]

For hunting, would heavy bullets be effective even without the highest velocities?

 

[jeepman4804]

Depends on what you are hunting. Higher velocity with a big 255gr bullet will allow deeper penetration and punch through bone without as big a lose. Think hogs with their thick skulls and breast plate, or other muscular animals with deep chest cavities.

 

[Dixie Gunsmithing]

g.willikers,

I cant remember if it was about the .45/70, or the .444 Marlin, but one was said to have the knockdown force of a 12 ga. slug. That was one of the reasons that the US adopted the .45 caliber pistol round, due to its shock and knockdown power over smaller rounds. So, big slugs do help. However, looking at the difference between say the .44 mag, and the .444 Marlin, they say the .444 Marlin has the same power at 200 yards, as the point blank range of the .44 mag. being fired from a pistol. I think I read that on Wikipedia about the comparison. Of course I'm getting out of pistol cartridges here and into rifle.

 

[jeepman4804]

So I received the new springs and was excited to get to playing, but I ran into a little snag. The springs are either too long, or something else is out spec. Sig uses standard mainspring housings. They are box stock Hogue Piranha G10 Magwell grips/mainspring housing. I did not base them being too long simply due to a visual inspection. I installed them and then attempted to cock the hammer flush to the grip safety and they would not cock without binding up the hammer and sear. They are actually so long is started to defect the hammer strut. This indicates to me that the springs were stacking. After removing about a coil and a half the problem went away.

My concern is will this cause a long term problem or greatly reduce the springs tension? I called Wolff and was told the expert was out until next week and they could not answer my question. I ended up putting the "34lb" shortened spring in and ran it without any issues at the range today. I ran standard 230gr ball and 230gr HST +p without a stoppages.

I ran 230gr ball just to see if I could leave the heavy mainspring in it for .45super/450 SMC and still run my duty and range ammunition. Trigger pull went from 3.5lbs using a 21lb mainspring to 3.7lbs with the cut "34lb" mainspring.

I was able to tear my pistol back apart to get measurements.

Mainspring housing bore depth is 1.687" and bore diameter is .282" with the schematics showing housing bore depth of 1.672" +.006" -.000" and a bore diameter of .280" +.003" -.000"

Mainspring cap measured .747" total height, the head height being .138", and hammer strut seat depth of .047" with the schematics showing .75" +.000" -.005", head height of .142" +.000" -.006", and hammer strut seat depth of .063 +.010" -.000"

Mainspring housing pin retainer measured .530" in total height and schematics showing .530" +.000" -.100"

I was unable to remove the hammer to check strut length due to the majority of my tools being at my parents place, but the only thing that is noticeably off is the hammer strut seat depth on the mainspring cap. It is .016" shallower than minimum and .026" shallower than maximum. The spring coil diameter of the 34lb Wolff spring is .05" per coil. So even if it was in spec then it would still bind uncut. I am kind of leaning towards purchasing a new cap and pin retainer from Wilson and trimming the hammer strut to 1/16" preload with the slide on. Any input on this?

I am a little scatter brained currently, so if I missed any pertinent information needed to help me ask please ask.

Thanks,
Clay

 

[RickB]

What about using a removeable MSH cap pin, a la Springfield's ILS system, to allow the stock MSH internals to ride a little higher? Cut the strut to the length that allows full cocking, while still fully supporting the cap when the hammer is contact with the firing pin? It might buy you .10", or so?

 

[Hunter Customs]

I believe the stock mainspring weight in a 1911 is 23 lbs.

I was going to recommend a 25 lb mainspring so your 26 should be fine, a 18 lb recoil spring, a square bottom firing pin plate from EGW with a small radius at the bottom as close to the radius of a .062 drill bit as you can get it, however make sure it's no larger.

I would also consider a shock buff but I would mill my slide so the shock buff does not cause short stroking.

Best Regards
Bob Hunter

 

[jeepman4804]

I ran the "34lb" (lacking 1.5-2 coils) with a Harrison Design FPS (basically the corner is just broke with no real radius), 17lb Wilson Flat Spring recoil spring and Wilson Buffers when I went to the range. Huge reduction in felt recoil/muzzle flip while shooting Federal 230gr HST +p and it ran perfect with standard ball. It ate the Wilson Buffer after about 75 rounds of the HST and I had to use the slide stop to release the slide as the buffer would not allow me to slingshot it.. Gonna order son CP Buffers to try, but they will be range only. I think I am gonna just slightly trim the hammer strut and turn down the bottom of the MSH cap.

 

[Hunter Customs]

Buffer after about 75 rounds of the HST and I had to use the slide stop to release the slide as the buffer would not allow me to slingshot it.. Gonna order son CP Buffers to try, but they will be range only.

Eating the buffer up quickly and not being able to slingshot the slide is what I was referring to about the slide needing some milling to keep it from short stroking when using a shock buff.
As for shock buffs CP Buffs were always my first choice, the only ones I stocked in the shop.


Best Regards
Bob Hunter

 

[RickB]

I have a Colt .45 that will eat a Wilson buff in about 200 rounds of 200@850 loads, because the edges of the recoil spring tunnel are very sharp, rather than because the slide is recoiling very fast.
I had a Cominolli frame-saver guide rod in my Delta Elite for many years, and had to change the buffs (on both sides of the guide rod head, so there's no metal-metal contact) only once in maybe 1000 rounds.
Check the slide to see if you're cutting the buffs instead of or in addition to pounding them.

 

[Clark]

http://www.gunsprings.com/faq

3. What weight recoil spring should I use with a particular load?
This is a very common but hard question to answer in exact terms and in most cases an exact answer is not possible. There are many factors which influence the correct weight recoil spring to use. These factors include the particular ammunition brand and load, individual pistol characteristics, individual shooting styles and your individual, subjective feeling of how the gun shoots and should feel.

The factory spring weight is designed to operate the pistol with what would be considered average loads, plus or minus a little. It is not uncommon for manufacturers to specify what they consider a factory ammunition load.
In general terms, the heaviest recoil spring that will allow the pistol to function reliably is the best choice - tempered by the above factors. As a rule of thumb, if your spent casings are first hitting the ground in the 3 to 6 foot range, then the recoil spring is approximately correct. If you are ejecting beyond the 6-8 foot range, then a heavier recoil spring is generally required. If your casings are ejecting less than 3 feet, a lighter recoil spring may be needed to assure reliable functioning.

Taking these factors into consideration, it then comes down to how the gun feels and performs when shooting - in your judgment. However, using too light a recoil spring can result in damage to the pistol and possible injury to you.

Here is what I did. Notice how much more force it takes to cock the hammer while pulling back the slide.

When I calculate how much it takes to move the slide back vs how much momentum is in the bullet and gas, I am losing half the energy somewhere. It turns out it is in moving the frame, hand, and arm.

Only half the bullet and gas momentum shows up in slide relative to frame movement.

pic above same as link below