Flat wire Springs for SSG use

[Nvreloader]

Tim
Here is some info for you, on Vari-rate recoil springs, 

From the Wolff Gunsprings site,
https://www.gunsprings.com/index.php?page=FAQ

1. What is the difference between conventional and variable recoil springs?
The difference is both physical and operational. With a conventional spring, all the coils are spaced equally apart, except for the closed ends. In a variable recoil spring the space varies between coils with less space between coils at one end and more space between coils at the other end.

The way the two springs store energy is also different. For example if a conventional recoil spring is compressed 1/2", it might store 1 pound of energy. For every additional 1/2" this spring is compressed it would then store 1 additional pound of energy. When a variable recoil spring is compressed 1/2", it might store 1/4 pound of energy. The next half inch of compression might store 1/2 pound, the next half inch might store 3/4 pound and so on. In other words, a conventional spring stores energy on a straight line and a variable spring stores energy on a curve. If both springs are rated at 16 pounds, they will both store 16 pounds when compressed to the same working length, but the way they get to 16 pounds is different.

Sbrower
Thanks, looks like we are felling our way along this dark rabbit hole, 
gives me an Idea....

Tia,
Don

[sbrower]

Nvreloader, Here are the specs you asked about on my QB big bore build as they relate to SSGs and flat wire springs. Sorry for the long post:

General specs: QB78 starter rifle, 24" TJs .357 cal 1:26" twist barrel, 3000 psi custom tube with 188 cc plenum, PEEK poppet, 0.28" port, 0.313” valve throat. With 2900 psi starting fill and 152 grain cast bullets, the 3+1 hunting tune is 784-782-770 fps for an average of 205 ft-lb at 2% ES.

This build is intended for hunting but was initially tuned to a 2100 psi fill because I was hand pumping. At a 2100 psi fill, the rifle produced around 135 ft-lb. This low-pressure setup used the factory hammer (bumped up in weight to 67 grams), and an SSG with conventional 0.049” round music wire. The SSG produced a hammer strike of around 10 in-lb for this low-pressure tune.

The design energy level of this rifle is +200 ft-lb at a 3000 psi fill, so more hammer strike was needed. A heavier custom hammer was made that weighed 116 grams and has a stroke of 1.01”. No fancy calcs for this hammer, just the largest one that would fit into the 4.4” of space between the valve stem and the rear tube cap in a QB. The hammer is 0.74” diameter by 3” long. It has a 0.438” diameter by 1.43” deep hole drilled in the end to receive the SSG. When cocked, the forward (muzzle) end of the SSG protrudes into a clearance hole in the hammer that is 0.313” diameter by 1.20” deep. The sliding end of the SSG rides against the shoulder between the smaller and larger diameter holes. The SSG for this hammer has a compressed spring length of 2.7” and a gap 0.025”. Pics of the two hammers are show below, factory hammer is the lower one.

I initially used a conventional round music wire spring in the SSG: 0.055” wire, 3.15” long, 18 lb/in spring rate. Crunching the numbers shows this SSG/spring combo yields a hammer strike of about 16 in-lb which was enough for the 3000 psi fill. However, the 26 lb peak cocking force was uncomfortable and the spring began to take a set which cause the rifle’s energy fall off. When I tried longer, smaller wire springs to reduce the peak cocking force, they became coil bound or did not delivery the needed energy. Enter the flat wire spring.

The flat wire spring allows a long spring to compress into a much smaller stack of coils compared to a round wire spring. This allows a very long spring at a lower spring rate to be compressed on to the SSG without going coil bound. The result in a couple of things: 1) A higher initial cocking force - because a 6 inch spring is being crammed onto a 2.7” SSG, and 2) A lower peak cocking force - because we are “only” compressing the spring another inch during cocking.

The first flat wire spring tried in this build was for a Glock model 19. The spring was designated as 22# at full recoil (using the handgun rating method). This spring was about 6” long and had a spring rate of 4 lb/in. Crunching the math yields a hammer strike of 12 in-lb, which enabled a fill pressure of 2500 psi. Next a Colt 1911 G.M. spring was tried (24# at full recoil), which turned out to be the same wire as the Glock spring. This Colt spring was 7” long and had a spring rate of 3.5 lb/in. Crunching the math showed that I needed 9.5” of spring to yield the desired energy. So the Glock spring was chopped and added to the SSG along with the full length Colt spring. Total combined length was 9.4” and the spring rate was 2.5 lb/in. This gave the 15 in-lb needed to enable a 3000 psi fill. Peak cocking force is a comfortable 18 lb, a noticable reduction from the 26 lb peak of the equivalent round wire spring.

The assembled SSG is shown in a photo below. Note how many coils were used without the SSG going coil bound. The sliding spring spacer is to keep the two springs from winding into one another.

[mackeral5]

Nvreloader, Here are the specs you asked about on my QB big bore build as they relate to SSGs and flat wire springs. Sorry for the long post:

General specs: QB78 starter rifle, 24" TJs .357 cal 1:26" twist barrel, 3000 psi custom tube with 188 cc plenum, PEEK poppet, 0.28" port, 0.313” valve throat. With 2900 psi starting fill and 152 grain cast bullets, the 3+1 hunting tune is 784-782-770 fps for an average of 205 ft-lb at 2% ES.

This build is intended for hunting but was initially tuned to a 2100 psi fill because I was hand pumping. At a 2100 psi fill, the rifle produced around 135 ft-lb. This low-pressure setup used the factory hammer (bumped up in weight to 67 grams), and an SSG with conventional 0.049” round music wire. The SSG produced a hammer strike of around 10 in-lb for this low-pressure tune.

The design energy level of this rifle is +200 ft-lb at a 3000 psi fill, so more hammer strike was needed. A heavier custom hammer was made that weighed 116 grams and has a stroke of 1.01”. No fancy calcs for this hammer, just the largest one that would fit into the 4.4” of space between the valve stem and the rear tube cap in a QB. The hammer is 0.74” diameter by 3” long. It has a 0.438” diameter by 1.43” deep hole drilled in the end to receive the SSG. When cocked, the forward (muzzle) end of the SSG protrudes into a clearance hole in the hammer that is 0.313” diameter by 1.20” deep. The sliding end of the SSG rides against the shoulder between the smaller and larger diameter holes. The SSG for this hammer has a compressed spring length of 2.7” and a gap 0.025”. Pics of the two hammers are show below, factory hammer is the lower one.

I initially used a conventional round music wire spring in the SSG: 0.055” wire, 3.15” long, 18 lb/in spring rate. Crunching the numbers shows this SSG/spring combo yields a hammer strike of about 16 in-lb which was enough for the 3000 psi fill. However, the 26 lb peak cocking force was uncomfortable and the spring began to take a set which cause the rifle’s energy fall off. When I tried longer, smaller wire springs to reduce the peak cocking force, they became coil bound or did not delivery the needed energy. Enter the flat wire spring.

The flat wire spring allows a long spring to compress into a much smaller stack of coils compared to a round wire spring. This allows a very long spring at a lower spring rate to be compressed on to the SSG without going coil bound. The result in a couple of things: 1) A higher initial cocking force - because a 6 inch spring is being crammed onto a 2.7” SSG, and 2) A lower peak cocking force - because we are “only” compressing the spring another inch during cocking.

The first flat wire spring tried in this build was for a Glock model 19. The spring was designated as 22# at full recoil (using the handgun rating method). This spring was about 6” long and had a spring rate of 4 lb/in. Crunching the math yields a hammer strike of 12 in-lb, which enabled a fill pressure of 2500 psi. Next a Colt 1911 G.M. spring was tried (24# at full recoil), which turned out to be the same wire as the Glock spring. This Colt spring was 7” long and had a spring rate of 3.5 lb/in. Crunching the math showed that I needed 9.5” of spring to yield the desired energy. So the Glock spring was chopped and added to the SSG along with the full length Colt spring. Total combined length was 9.4” and the spring rate was 2.5 lb/in. This gave the 15 in-lb needed to enable a 3000 psi fill. Peak cocking force is a comfortable 18 lb, a noticable reduction from the 26 lb peak of the equivalent round wire spring.

The assembled SSG is shown in a photo below. Note how many coils were used without the SSG going coil bound. The sliding spring spacer is to keep the two springs from winding into one another.

Very cool build, thanks for sharing. 

[Nvreloader]

Sbrower

Don't worry about being long winded, it provided lots of info and the photo's were great.

Thank you for providing it.

Questions for you,
What SSG/flat spring adjustment levels did you try, or did you try for max only,
with the OEM or your new hammer?
What do you think of the flat springs for your application?
Would you use them again, if they fit what you are doing using an SSG type 4 design?

Wolff brand 1911 recoil springs have a Vari-rating's, in several rates, might provide other options.
 
I have used lots of them for my Coonan 357 Mag 1911 style pistols,
with very good results, but they are round coil wire types.

Thanks,
Don

[sbrower]

Don,

Sorry for the delayed reply, but I am winter camping in Arizona and do not have regular internet access. Just a note: Arizona is awesome for air gun hunting!

I did not try to build an adjustable SSG for this QB357. I was struggling to get enough hammer strike, so I built an SSG that utilized all of the available room in the QBs rear tube area - leaving maximum space for the spring so that it did not go coil bound. If I had needed some additional preload, I still had a little space to shim the SSG, but did not end up needing to.

If I were to do the project over, I would change the sear engagement location on the custom hammer to provide a longer cocking stroke. This would allow an even lower peak cocking force for a given hammer/cocking energy.

This QB357 required more hammer strike than could be achieved using conventional round wire springs (at reasonable cocking forces anyway). The flat wire spring used on the SSG as described in the earlier post was the only spring configuration that could store enough energy without becoming coil bound. I will definitively use these flat wire springs in future high-energy builds, or whenever a long spring with a relatively low spring rate is desired to reduce peak cocking force.

Hope this helps...

[Nvreloader]

Just bringing this post/info back up to the top, and hopefully others will add more info etc.

Since I have a new 22 cal Gauntlet, I'll be using a flat wire spring on the SSG,
I plan to install in it, from the info I have received, the Gauntlet is just a refined QB.

The cocking force on this Gauntlet is Rude, Crude and Sociably unacceptable , or just plain horrible,
it is just about all I can do, to cock it with my bum right hand/wrist,
as soon as the newness wears off, it will get a complete make over, with a SSG installed etc.

Tia,
Don

[KnifeMaker]

Looking forward to your findings Don, and will then STEAL it for my BNM modded Maximus. LOL!!!


Knife

[Nvreloader]

Knife
You don't have to steal it, I'll give it to you free..........

From the diagrams I have seen so far,
I think I can get a #4 type SSG in the Gauntlet,
It is getting up enough nerve to tear it apart and my the conversions etc.

So far for the Gauntlet 22 cal, is really showing her stuff,
starling at 40 yds+ are a gimme shot > 1S1K for far, the HOSP are running about 50% hits.
I think, I need to do some accuracy work to improve it overall.

Tia,
Don

[KnifeMaker]

No common house sparrows here, but I've Been giving the cow birds a hard time. I think the bullets are a bit of overkill.  


Made a single shot tray from a mag bumper. Well,  what I think was a .380 mag. bumper that I found on the range. Works perfectly. LOL. Fit the mag slot with no mod's and was rubbery, so holds itself. Just had to shave off the top and add a trouft.


Mike

[mackeral5]

Adding an update to my flat wire spring experience....  The 1911 recoil spring seemed ok for a while, but lock speed was a bit sluggish compared to my normal setup---to the point of effecting accuracy at 100 yards. 

Cocking effort was reduced with the 1911 spring, however it just didn't suit my needs.  I switched back to a QB78 spring in my SSG.  This spring with considerable preload and a bit more SSG gap results in a much more snappy shot cycle. 

Your mileage may vary....

[rsterne]

I'll just offer an opinion here on progressive springs for use as hammer springs.... This applies regardless of whether they are round or flat wire....

The "bad" part of cocking a PCP occurs during the last part of the cocking stroke, when the force is the highest.... A SSG allows a higher initial cocking force, so for the same AVERAGE force, and therefore the same hammer energy and momentum, the force required at the end of the cocking stroke is less.... That is one of the primary advantages of the SSG, provided the proper longer, softer spring is chosen.... It can open a given valve with less peak force required at the end of the stroke....

Why is the end of the stroke the most important part?.... That is the force you must overcome to get the hammer to engage the sear.... If the force required rises suddenly in the last part of the movement (like it does with a stiff spring with a gap to the hammer, an SSS), you are more likely to not QUITE pull it back far enough to cock the gun.... This is particularly bad if the gun is a repeater, because when you pull it back a second time, you may double load pellets.... Conversely, if you have a significant preload on the spring (like you do with a properly designed SSG), your muscles have to develop more force just to start the bolt moving back.... Since the spring rate is lower, the force rises less quickly (starting from a higher base), and you don't notice it as much.... making it more likely that you will complete the cocking stroke.... The PERCEIVED peak cocking force is also less, because you don't have that quick increase that you see with a spring with a high spring rate....

Considering all of the above.... WHY in heaven's name would you want a progressive spring that requires more force at the end of its stroke to develop a given hammer energy and momentum?.... That seems completely the WRONG way to go.... 

On the other hand, using a flat wire spring would seem to be a good solution for an SSG, as it will fit in a shorter space.... On the other hand, it will, of course, require more space between the ID of the tube (or hammer) and the SSG limiting rod running through the middle of it.... because the "thickness" of the flat wire spring (difference between ID and OD) is greater for the same force.... You are simply arranging the steel in the spring wire into a wider but thinner (and therefore shorter) space.... 

Bob

[Nvreloader]

I'll just offer an opinion here on progressive springs for use as hammer springs.... This applies regardless of whether they are round or flat wire....
"On the other hand, it will, of course, require more space between the ID of the tube (or hammer) and the SSG limiting rod running through the middle of it"....
"because the "thickness" of the flat wire spring (difference between ID and OD) is greater for the same force....
You are simply arranging the steel in the spring wire into a wider but thinner (and therefore shorter) space.... 
Bob

Bob
I am not sure, I am following you on the above information about the flat wire spring, (underlined)?   
Help me to understand...............

Most of these flat wire springs are made to fit inside the spring tunnels of the major brands of semi auto pistols, among other applications,
which run about .420" inside diameter and have spring rod guides diameters from .250" to .320" +/-.

The inside diameter of the QB/Gantlet hammer hole is around .375/.380", with an Outside hammer diameter of .740" +/-,
so yes, the spring and other parts would have to fit on the end of the hammer, but would not be any larger than 1/2" diameter etc.

I do not know what the dimensions of other AG's hammers/tubes are etc.

Tia,
Don

[rsterne]

It seems pretty obvious to me that to be of nearly equal force, the wire in a flat wire spring must be wider if it is thinner.... The wire in the two springs you mentioned in your OP were 0.072" and 0.074" wide.... Since it is wider, that means that the difference between the ID and the OD is greater.... That may or may not be a problem, but for example the SSG I use in my 2260 HPA fits over a 1/4" guide and inside a 3/8" hole in the hammer.... That leaves only 1/16" of clearance between the two, so a flat spring where the wire is wider than 0.060" would bind on either the inside of the hammer or the guide rod....

The spring in a 22XX/Disco or a QB sits inside the hammer.... having it sit behind the hammer only would mean that the tube is too short.... Just an example.... It may be a problem on some guns and not on others....

Bob

[int3man]

OOPPSS Please Delete.