Canadian Airgun Forum

Anyone shop for Nitro Piston gas rams retail?

These springs seem to be made for different purposes (furniture, vehicles, load stabilizers, etc), and though Crosman's spring is a bit unique in dimensions, it seems like a reasonable configuration to obtain retail - smaller/larger ones are certainly on the market.

Length: 260mm
Body length: 150mm
Spring length: 110mm
Body diameter: 19mm
Spring diameter: 8mm

For instance, this one (worksafe link obvs) : https://www.mscdirect.com/product/details/69150829 is NOT identical, but it's close enough to give me hope.

Pretty sure something dealing in such high pressure isn't something you'd want to guestimate. If I did find a perfect fit re: dimensions, does anyone know about "Max Stroke" (mm's) and "Initial Charge Pressure" (psi, kgs/m2) of the Crosman Canadian piston "BT5M22-00-1A"? If those could be matched, you might get a better quality piston.

For those with PAL's, you could get one of the discontinued piston configs to upgrade your airgun to USA standards.

When I needed a full strength gas ram I clicked buy, 2 weeks later it was in my mail box. https://www.ebay.ca/itm/153295973100 They are almost sold out now so now I would click here https://store.gravelagency.com/gaen/bt9m22-00-5a-replacing-bt9m22-00-5-gas-spring.html

For some reason this gas ram doesn't come up on Crosman Canada but does on Gravel. Anything $50 and over on Crosman Canada is free shipping

For under $70 I would not spend a bunch of time trying to find something that would kind of fit

Robert

Thanks, Robert, I ordered the Ebay one from Australia. Others have mentioned successful receipt of that piston in Canada, and while I don't claim to know anything about what is or is not permitted, this piston is a replacement for 'obsolete' one that was sold legally to the Canadian market & many people own them, without PAL's. Perhaps Crosman took ownership of the ease of modding & changed it, but it's not like a nitrogen piston is that hard to make.

Appreciate the help, will update my posts to prove any success/failure in my mods.

Hi McRobert, just thought I'd mention that I did try to put that bt9m22-00-5 gas spring in my cart & check out at 'gravelagency', but it wouldn't allow it. I use a VPN so my IP will show up as an American one, but even without the VPN, the link showed available stock but just wouldn't let me check out. I had to create an account to even try to buy it.
I'm not sure if you know who hosts that page or know anyone looking to sell those springs, but while I wait for the one I ordered on Ebay, I don't mind hedging my bets & sourcing it somewhere more 'local' than Australia. I've beaten this topic to death, but I just got a FPS chrono & I'm testing my Crosman F11 (.22) performance with the OEM spring. I noticed in the Buy/Sell/Trade you sold one just a few months ago, they're in demand. If you happen to know a Canadian who'd be willing to sell theirs, Ill pay 'handsomely'. That does sound kind of creepy, doesn't it...but I'm on the level. I get into a hobby, I go in all the way. I mean, it's a tiny piston with only 60kgs of snap. You'd think gas springs would be available everywhere!

Got the "Franc Moody Ballistic Precision Chronograph" from Amazon today (~$80), it's not bad for my purposes

Just FYI, my Crossman F11 gets good FPS with Crosman Premier hollow point .22's, 14.3gr:

469
471
464
474
463
451

With Ruger 'Superpoint' hunting pellets (17gr):

424
417
419
411

Would you suggest a specific pellet or pellet type that could improve FPS with the stock rifle? Smaller weight, maybe a rounded tip? I'm leaning on you here so no need to reply at all, just whatever advice you've got, fire away. Sorry for the pun!

Disregard.

Those FPS counts were after shimming the gas ram inside the piston with 3 dimes. I did lots of experimenting with shimming.

Without a shim, the OEM FPS is max 452 FPS with a 14.3gr pellet & 395 FPS with a 17gr pellet.

I expected Crosman's OEM FPS to be a little weak, but without a shim, I do disagree with Crosman's claim of "this is not a toy". No wonder people get their PAL, the restrictions on these things are over the top. Not sure what I was worried about re: mods putting this thing into PAL territory. Tried a wide variety of shim depths, positions & locations & the most I could get from my 495 FPS Crosman F11 .22 cal pellet rifle was 474 FPS.

Reliably, 460 FPS is all this rifle will get even with shims. I'll try some lighter pellets soon (10gr) to see how they fly, but I'm confident this rifle will remain @ legal performance no matter what it's shimmed with. I never tried adding a spring to compliment the gas ram, that seems like it might help if one could drop one in with the gas ram somehow.

It's true these gas rams are pretty uniform no matter how deep the pre-load. I tried 4mm, 5mm & 6mm of shim depth, either at the front of the inside of the piston or at the back cap, whether the gas ram is pointing spring-to-front or spring-to-rear it didn't seem to matter. The FPS gained from shimming is approx. 20 fps. The piston is oiled properly, the gas ram is clean & dry. I would recommend anyone with a gas ram wanting 20 more FPS, to add ~4mm of shim depth (3 dimes) to the anterior of the front of the piston (X marks the spot):

<- ( {X} [[[[[[[[[[--------- )

Pull the gas ram out, drop 3 dimes in so they're flat inside the piston, put the fat end of the gas ram in toward the front, close it back up again. Easy - but 20 FPS is all you're getting, and that will not put you at risk of PAL'ing your air gun - nor will you gain FPS by doubling the amount of dimes or pennies you throw in.

Interesting info.

_________________
Best Wishes
Daryl

I tried more than a dozen different pellets with this very .22 F11 over the last 8 months. Without a chrony, I cannot provide FPS readings but I can suggest best precision choices based on many hundred shots — all from the same distance but across 3 seasons.

Number one: H&N Baracuda Hunter. Tied for second place: Predator Polymag shorts and Gamo Red Fire. Third: H&N Terminator. For some reason I cannot wrap my head around, The H&N Baracuda Hunter Extreme and Crow Magnum were less precise despite almost identical 18gr weight and very similar shapes.

I had high hopes for the H&N Hornet, based on stellar Amazon reviews (and premium price point) but you never know where the next one will land. Likewise, the Stoeger X-Hunt dissapoints. It seems lighter ones have a harder time so I also tried the 21gr H&N Match; decent but no more precise than all the others so it would seem that the sweet range is between 15.4 and 18.2 grains.

I thought that Crosman products would have been the best match for the F11... what a joke. Both the hollow point and the pointed ones are the worst; I am now pretty sure it has a lot more to do with the 14.3 gr weight than manufacturing quality or design.

I just received the Custom Air Seals 60kg ram in the mail today (2 weeks transit) and I have already swapped the piston for the shorter one so... I will now have to a) get a chrony — thanks for the reco — and b) retest all pellets to see wich will fare better at higher velocity.

Ok, I've got to ask - has anyone ever experimented with even stronger gas rams? The one I just got is 60kg & it should be fine. There's one for sale with 70kgs, though it's 4mm shorter, a shim could make that fit...
I'm casually testing the limits of the Nitro Piston tech. If Crosman sells .22 cals that get 1000 FPS +, then they must have some pretty serious gas rams. Is it legal/ethical for someone with a PAL who owns a Nitro Piston rifle that gets 1k FPS + to sell the gas ram (and only the gas ram) to someone who doesn't? What about a gas ram manufacturer simply selling one to spec to someone with no intent implied other than to buy the piston?
Or is it more than just the piston? What about the higher powered .22 cal break barrels is different from the < 500 fps offerings on the CDN market? Is it piston travel length, size of the compression chamber, caliber of the transfer port? Are different materials used? Would a trigger release mechanism made for the BT5M22 gas ram have to be upgraded for a 70kg gas ram?
I'm not a narc, LEO or journalist - I'm a tinkerer & I'm curious. Think of me as an intellectually disabled Iron Man with a very small budget. I'm just not keen on being told what I can't do (within reason)...

e.g., I have a radar detector but I'd never speed in a school zone. Your sister's hot & drunk but I'd still make sure she got home safe & untouched. I have scruples, lol!

Someone who owns the 1,000fps gas ram can legally sell it to a person who doesn't have a P.A.L. because the gas ram is a tool or combination of machined parts, etc,
but it is not classified as a firearm (yet).
That person could not legally sell that same person a P.A.L. air rifle.
Seems to me now, before any "firearm can be sold", a call to the CFO must be done to get a # for selling it and the buyer's P.A.L. # is used, thus it is basically registered to the buyer's P.A.L.

Weihrauch makes gas rams that run OVER 1,000fps, as noted in your other thread. HW90 in .177 does this.

Furthermore:

"Furthermore, unlike any other gas ram airgun, the HW90 has the built-in capability to change the pressure inside the gas ram – and therefore the power. True, it requires the use of a separate, additional cost, pump and gauge, but it can be done."
"The average Standard Deviation – shot to shot variation across a string – was 6.37 FPS across the standard range of HAM test pellets. It fell to just 2.82 FPS for the H&H Field Target Trophy pellets."
"What sort of pressure is in the gas ram? According the the factory, it’s typically around 23 to 24 bar (approximately 330 to 350 PSI)."

_________________
Best Wishes
Daryl

Hey guys, all of you who've taken so much of your time helping me & advising me on all things, I'm learning so much still, but wanted to let you know that my recent experiments with different parts have resolved the issue I was having with my F11.
Daryl, McRobert, ricksplace, etc, you were all careful to keep the advice ethical & legal & I was led to the right topics where I investigated things on my own. YouTube was also helpful in my determining what I was missing towards resolving this issue.
I spent a lot of money on parts, as well as SO many hours comparing different models, trying to rescue my F11 from its sad origins. I completed my mods yesterday & spent a couple of hrs tonight verifying they worked. I finally found the right parts & have my airgun exactly how I want it.
Success.
Let's see if I can find something else I don't like about this airgun so I can start fixing it!

Slob, I used your dimensions to find Asian supplier of gas rams, they have gas rams up to 120 kg. I have ordered 2 rams in the size at 56 kg for $7 each. I have a few guns that I try these in. At present I have mine shooting 9.5 gr at 540 fps and would like a bit more power but to full power. I will link and update once they are received


Robert

Hey Robert, thank you! I wouldn't make any efforts on finding rams that have more stank than the 70kg one I have, but appreciate it all the same.
One thing that stood out for me in my testing was, how people would sand down the piston seal to create more room in the chamber for air - I had no idea how precious air volume actually was, that shaving off a millimeter of seal would make a difference. But why should I have to lose valuable piston material. Then it occurred to me - why not source a shorter piston to increase the length of the piston travel just a bit, as long as it could be cocked to the locking position, was what should solve my issue. You'd have to back the piston up a bit somehow to compensate, though, not too far that it became a pre-loaded mess, but shorter all around, including the gas ram body.

It would be certainly harder to cock it, and the barrel would have to bend farther so the lock groove still reached. I read up on Crosman's 'NP2' tech, which was based on that concept. A larger angle reportedly makes cocking easier as the angle increases. Can verify.

I put 'PCP Only' pellets into my airgun (accidentally bought them & shot about 30 of them without reading that) but they're 14.66gr, so they're not too light. Something about the coating, I'm guessing, makes them faster than my 14.3gr Crosman 'Premier' hollow points. Link is worksafe, a Canadian Amazon link: https://www.amazon.ca/dp/B0077YDE5A?psc=1&ref=ppx_yo2ov_dt_b_product_details

My results are erratic but after about 20 shots, they 'level out', much like before when I'd notice the general FPS decrease steadily, then I'd get one faster shot, then another 10 or so showing a very slow decrement, then another fast one.
Last night was just a FPS check. Tonight I'll work on accuracy. I'd like to try heavier pellets though. First shot after letting the airgun sit overnight is always the fast, and usually diesels. I see now why there are people who try to get their airguns to diesel on purpose - but that's not for me. I like it quiet.

My intent as you know was to improve the brutal 420fps to around 490fps so I'm getting my money's worth but staying within the Canadian limits.
I can't imagine what a 120kg ram would do, lol, I could rig one into my father's La-Z-boy to stand him up like a catapult! 120kg, good cheeses cripes, I'd hate to be the poor piston getting slammed by that!

How they actually fit in the barrel, will make a difference in velocity and 2 close-weight pellets could easily swap positions.
I've never heard of PCP only pellets. I shoot the same pellets in my PCP's as I shoot in my springers & visa-vis.
As you shoot with a springer, the metal heats up, which will pre-heat the air. Warmer air contains less air molecules than cold air
thus warmer air has less actual 'usable' volume.
Compress less volume, get lower results.
Same with automobile engines. Cooler air, more power. Hotter air, less power.

_________________
Best Wishes
Daryl

How they actually fit in the barrel, will make a difference in velocity and 2 close-weight pellets could easily swap positions.
I've never heard of PCP only pellets. I shoot the same pellets in my PCP's as I shoot in my springers & visa-vis.
As you shoot with a springer, the metal heats up, which will pre-heat the air to a higher temp than cooler air & a cool system. Warmer air contains less oxygen molecules than cold air
thus warmer air has less actual 'usable' volume.
Compress less volume, get lower results. Same with internal combustion engines. Cooler air, more power. Hotter air, less power.

_________________
Best Wishes
Daryl

Just an assumption on my part, right or wrong.

_________________
Best Wishes
Daryl