Put the HPA tank on the Sig today


I was averaging close to 400 fps with Co2, but the velocity dropped with the high pressure air for some reason? I only avg about 350 fps now, but heck I can live with that since I don't have to buy Co2 cartridges anymore.




Likely the regulator pressure is higher then the CO2. This causes the valve to be harder to open (with the same spring).

You can get the velocity back in one of two ways. First way is to increase the hammer spring. Not sure if this can be done on the Sig. Other way is to lower the regulator pressure. This can be as simple as degassing and removing a shim from the reg.

If you keep shooting the gun (over the chrony) till the pressure is down to the regulator set point you should see that the velocity will increase as you go below the regulated pressure.

That is interesting. But we all have experienced this in our PCP rifles, especially the unregulated ones. . I was just looking at the Sigs & would want the HPA. You would think the dealer selling the Sig & HPA tank should know this. I have an extra 400 cc bottle from an FX. I might get one of those 800 psi regs with the 18X1.5 mm male thread. I would bet it would be hard to increase the Hammer Spring in the Sig, I kind of think it would make the trigger pull harder???
 

I was averaging close to 400 fps with Co2, but the velocity dropped with the high pressure air for some reason? I only avg about 350 fps now, but heck I can live with that since I don't have to buy Co2 cartridges anymore.




Likely the regulator pressure is higher then the CO2. This causes the valve to be harder to open (with the same spring).

You can get the velocity back in one of two ways. First way is to increase the hammer spring. Not sure if this can be done on the Sig. Other way is to lower the regulator pressure. This can be as simple as degassing and removing a shim from the reg.

If you keep shooting the gun (over the chrony) till the pressure is down to the regulator set point you should see that the velocity will increase as you go below the regulated pressure.

That is interesting. But we all have experienced this in our PCP rifles, especially the unregulated ones. . I was just looking at the Sigs & would want the HPA. You would think the dealer selling the Sig & HPA tank should know this. I have an extra 400 cc bottle from an FX. I might get one of those 800 psi regs with the 18X1.5 mm male thread. I would bet it would be hard to increase the Hammer Spring in the Sig, I kind of think it would make the trigger pull harder???


I was looking at these a while back and (IIRC) I don't think increasing the HS was an easy job, that's why I decided not to pursue one.
 
Yeah, I am wondering about the action. Is it really Semi or a Double action? If it is Double action, increasing the HS would make it very hard to pull the trigger. but I still might get one. Seems everyone who gets one loves them. If is it is simple as getting a lower psi reg, that would be alright. Should give you more shots per fill as well? Oh by the way I love those old 600s. I had half a dozen, but am down to one. I never did the HPA , just suffered with the co2. Which was fine in the summer. I remember those big mags, but never seen one in person. I thought they was called Viper or something like that. 
 
Nutcracker, they have so many HPA conversion vids, I get lost!

https://www.youtube.com/results?search_query=sig+mpx+hpa+conversion

The lady from Sig says you can shoot all 30 shots in about 30 seconds if you have a quick trigger finger. But that's with Co2?

https://youtu.be/EnSoLZnXM2A

I like the way this guy ran a coiled hose trough the original stock and carried a buddy bottle

https://www.youtube.com/watch?v=-xsJnBoevcs

That almost tempts me to get the MCX with the 17.7" barrel and try the buddy bottle conversion on it?


 
I will watch those. The longer barrel should be more powerful, but the weight is almost a killer. The funny thing today I almost ordered one, but the reason I did not is PA did not have that HPA bottle set up in stock. Now I think I am just going to use my 400 fx bottle. If I decide to get one, that is. Keep us posted. Here is a thread a couple years ago, Urban Airgunner, I think. He got good groups with crosman destroyer. 

https://www.airgunnation.com/topic/sig-sauer-mcx-mpx/
 
Found a new set of iron sights for the Sig? LOL

1548039212_14649367255c45342cb8b6b1.59499557_50567699_2093076447401830_5622043741570203648_n.jpg

 
I'm thinking this would hook to my adapter on one end and hook to my Air Venturi bottle on the other end? I still should take a shim out of the regulator on my bottle to make sure the psi is well below 1100 psi. Would like to get it closer to 900 to 850 psi output.

https://www.amazon.com/gp/product/B01D98NOVG/ref=as_li_ss_tl?ie=UTF8&psc=1&linkCode=sl1&tag=kindleastore0f-20&linkId=bfb8c74f7ef445f13652bd9f31c6fda9

I think that setup is the same thing that guy used who threaded the hose through the stock tube. I am not sure I like the hose handing from the butt end, I think it would be less in the way just a couple inches back from the connection, but that might not be feasible. If you reduce your reg setting, let us know if your FPS increases. Whatever you do, don't increase it, these are co2 guns designed for low pressure not pcp rifles. 
 
That is pretty sweet Fuss. Nice change of pace gun, different kind of fun. I didn’t know you could convert them like that. That makes the idea of those a little more interesting.


Yeah , it would be nice if you could get at least 10 fpe of energy out of them though!


Ask and you shall receive............make it 11fpe and in 22 stock



https://hardairmagazine.com/news/hot-news-the-new-sig-mcx-virtus-pcp-air-rifle/

Now they have something. .177 pellets are to small for my bad eyes & fat fingers. Thanks for sharing. 
 
Woooohooooo, thanks for the heads up BTB & Nutcracker! I'll definitely hold off for a while and see how this plays out!

I've been busy cleaning out the airgun cabinets and storage. I've got tons of old/cheap pellets to run through these bad boys. Glad I kept them now!

I gotta get my mess better organized. Campfussell is a train wreck right now!

Thanks again

Fuss