[Qwazem]

I've been looking around this forum for a fair amount of time, but I can't seem to find a very conclusive answer as to the highest power spring the stock Bar-10 45 degree sears can handle in a sustainable way.

The reason I ask is because I recently figured out i'm shooting around 360fps with .25g bbs (i'm aiming to get as close to 400 w/ .25g as I can) and I am looking at buying PDI's 11mm 310 spring (they claim shoots 490fps w/ .2). I would try to cut this spring to shoot about 440 w/ .2's to stay under that 400 mark with .25's. I am also considering slightly cutting a PDI 260 or an AA m150.

Does anyone have experience with cutting PDI 11mm springs? I know they are variable pitch, so there would be some trial and error for how many coils to cut off and which ones. Also, I've read the spring cutting post on the forum already and to reach the FPS i am looking at, I would optimally want an M160 (impossible to find) or an SP140 (impossible to find).

Lastly, does anyone know where I could find a M160 or an SP140 spring in the USA?

I know the second/third part of this question has to do with my specific situation, however for the sake of having the first part be better documented I made the title about the maximum 45 degree sear spring power.

 

[Razinger]

Just get M150 and lip off a good 3 inches.


Razinger | The one, The only..

 

[kazuchan]

I used the spring had 540 FPS with .25g in PPS/ Matrix upgrades kit. But I'm scared it will hurt so I cut it down to 460.

540 FPS can be used but not sure it will be last long term...

 

[Qwazem]

Just get M150 and lip off a good 3 inches.

Razinger | The one, The only..

Sorry guys for the late response, but Razinger do you recommend the m150 spring for the FPS output restrictions I am under, or because the stock sears would not be able to handle much more than that? If it changes anything, I'm running a 510mm 6.03 barrel and am willing to buy upgraded sears (the zero trigger is a bit to pricey for me).

Is this from personal experience? If so do you know what setup you were using it in? I have an OK airseal where the cylinder holds pressure for about 30 seconds after the trigger was pulled.

I have an AA M170 spring I bought a while ago. Is there any reasonable way I can stay under 400 fps with .25's after letting it sit in the cylinder compressed for a while and cutting it?

Note, I have a post coming up describing the theory of the springs and some other questions involving its practical applications.

 

[threshold]

Qwazem I'd say that how much will your stock sears last largely depends on how good they were made, do take caution, some rifles starts slam firing with stock spring after a month while some works with stock spring and sear for a year. If you are going for stronger spring I'd recommend that you buy shs steel piston and trigger sears mabye later shs steel spring guide stopper. Sears go on ebay for around 30$ both so if you are on budget I'd recommend you those as it will last you much longer and you can go over 400 fps, maybe around 500, if budget is not an issue just buy some dedicated 90 degree system.

 

[Qwazem]

The sears are not a huge problem for me, its whether I can use the M170 I have to get to 400 fps w/ .25's or if I need to get the m150 hit that FPS target.

 

[kazuchan]

You can use stock spring with some spacers to reach 400fps xD ( I tried with brass spacers ( often came with hop-up unit or new bucking ) on AEG, work nice )

 

[Qwazem]

According to the spring cutting guide, the M170 settles into about 510-525 fps. If the AA M170 spring has around 50-55 coils (I forget exactly), This means about 10fps/coil. To reduce the FPS to around 440 with .2's (which converts to about 390 fps w/ .25's), I would need to cut 9 coils (just to be safe) which is, given that the VSR-10 spring is about 220mm uncut, about 36mm or 1.4in. The length of the uncut spring when sitting in the cylinder is about 2in. (This may be wrong, i haven't measured) less than when not, therefore I should be able to achieve 400 fps w/ .25's with a cut M170.

I've been working on post on spring theory, but this is the bit that is specifically relevant to this situation. This is a simplified description of what is actually happening, but for practical purposes I think it is mostly sound. What do you guys think?

 

[threshold]

I think that you can go with m150 to reach 400 fps with 0.25 bb. Yesterday I've installed action m150 (spring inner diameter 7mm) spring inside my gun and with custom 90 degree trigger I have I chronoed it just around 499 fps with 0.2 (that is with good sealing inside cylinder but I have ton of airleak on my hop up bucking), so I think that with 0.25 it would be above 400 fps allthough I didn't cut my spring. Btw why do you want to use such light ammunition?

 

[Qwazem]

Btw why do you want to use such light ammunition?

The field I go to chrono's with .25's

 

[Shockkandawe]

The 40 fps difference between where you are and where you want to be is quite small, and I have a feeling that if you added 1/2 inch of spacers or so and got your air seal to 100% you'd either be very close, or spot on.
As to your actual question of the max spring power on the stock sears, maybe the stock spring, maybe a 170. It varies heavily. That said I have a feeling that if you go with the m150 you're going to have to replace your sears before long. I personally would focus on the DIY mods and see how close you can get before swapping springs.

 

[Qwazem]

The 40 fps difference between where you are and where you want to be is quite small, and I have a feeling that if you added 1/2 inch of spacers or so and got your air seal to 100% you'd either be very close, or spot on.
As to your actual question of the max spring power on the stock sears, maybe the stock spring, maybe a 170. It varies heavily. That said I have a feeling that if you go with the m150 you're going to have to replace your sears before long. I personally would focus on the DIY mods and see how close you can get before swapping springs.
Today 09:55 PM

Thanks! Sometimes the best answers are the most obvious :doh:; I appreciate getting a clear response that answers the whole question :yup:

Also, any recommendations on what to use as spring spacers?

 

[Shockkandawe]

A very easy material to work is brass, any local welding/fabrication shop to you should carry various lengths and thicknesses. Personally I use stock and then make any modifications for cylinder size myself. Washers can also make easy spacers if you can find some that match your cylinder.

 

[Qwazem]

As a brief follow-up to this thread, I found some spent 9mm brass shells and cut off the base where the firing pin is, leaving only the front end. That brought me up to 406fps w/ .25g from 365fps w/ .25g. I got this down to 395fps w/ .25g by cutting off about 1/4 of the length of the remaining shell. The spacer started off about 14mm in length, so it ended up being about 11mm (i forgot to measure before installing it into my cylinder). My only advice if anyone tries this is to start trimming from the front end of the brass shell, because that is where the metal is the thinnest and easiest to cut.