4th test (CP1 co2 "MatchMaster" pistol)April 15 2017 at 2:48 PM
|gubb33ps (Login gubb33ps)|
Another stop on the CP1 co2 pistol journey.
Set myself a goal of a total of 300 foot pounds out of 1 12gr. with all shots inside of 3% varation AND something close to 5 foot pounds of energy. 60 shots at 5 foot pounds would be ideal, but I'd take 65 shots at about 4.6 foot pounds or 55 shots at 5.4 foot pounds (anywhere in that range).
Broke it in first, made a shroud, adjusted the trigger, found a reddot sight size I liked, and shot it enough to break it in.
Basically taking care of the little things while waiting for warmer weather for testing. Been 77-81F for all of the following tests.
HAve to pick some percentage of varation for comparison, and I really don't care if you pick 2%, 3%, 4%, 5% or 8%...so long as it's the same. Knowing co2's nature one's a rifle/pistol gets tuned up (when it drops off in speed, it drops off like a narcoleptic vulture) so I reworked the old tests with a 3% goal. (After all, what good is a low powered .177 if it's not accurate and consistant?).
To keep it kind of even, kept the same tin of 8.44gr. JSB's for all tests.
TEST #1. As issued (just well broken in):
3% for 42 shots...average ve. 509fps/ 4.86fpe / 204 3% foot pounds per 12gr.
TEST #2. Next serious testing, adjusted the striker spring tesnion down a little (by reducing the spring guide's "top hat" to the point where there was just a tiny touch of compression when the end cap went back on)and put a "buffer pad" on the face of the valve.
In retrospect, don't think the buffer did "jack".
3% for 48 shots...average 508fps/ 4.84fpe / 232 3% foot pounds per 12gr.
TEST #3. Got all serious about it and reduced the internal valve diameter by sleaving the inside. Basically restricting both gas flow and volume a little bit.
(you'll have to look up previous posts on that to get shot strings)
3% for 51 shots...average 508fps/4.84fpe/ 247 3% foot pounds per 12gr.
TEST #4. Went back inside and reduced the striker weight by 20%. Are those that say that 20% won't be noticed....but it hasn't worked out that way for me.
So with the striker reduced from 35 to 28grams (just picking 1oz/28grams as "good 'nuff").
3% for 59 shots...average 509fps / 4.86fpe / 287 3% foot pounds per 12gr.
DERN...so close....like 4% of goal close.
What I did notice in all of this is that the velocity didn't change. Thinking on that, can only conclude:
1. It's a gas hog in .177 as issued...squirting out more co2, mostly later than be used to drive the pellet. LArger bore (they do make it in .22...and in .25 in Europe) might make more use of that than a .177.
(To counter balance that, does seem (from other tests) this one is a bit fast compared to others. Just the random nature of acceptable tolerances of mass produced parts most likely).
2. After all the above, it's still shooting just as fast as when it started....so it might be time to look into strangling off the transfer port a little bit.
3. Looking at this shot count, think I rushed it a little and didn't let the pistol warm up to ambinat temp. Started slow, stayed a little slow until it found it's balance (warming up from outside temp. vs cooling down from shooting at a measured pace).
4. Likely, at back yard ranges, I'd have gotten to shot # 64-65 before noticing the velocity decline...just takes a lot of velocity change to be noticed at 15-25 yards.
SO....for that one reviewer that claimed +80 shots...my first reaction was "BS". Now I'm thinkin it "could be". Would be some "ifs". IF he was just plinking at short range and jusdging by the point of impact change (which would be pretty high....like 6-8%) AND if the pistol was spitting out pellets in the 4.0 to.4.3 foot pound range.
NOPe...still thinking BS.
|This message has been edited by gubb33ps on Apr 15, 2017 2:51 PM|
My sense, over the decades, is that ALL co2 pistols have strikers weighted
|April 15 2017, 4:17 PM |
#1...be as easy/cheap to manufacture as possible
#2..heavy enough to forestall valve lock under anything near "normal" temperatures
So all of them have strikers heavier than would be best for efficiency.
Now, I haven't messed with high end dedicated match pistols, and it's likely those have more carefully designed strikers. It would be interesting to see what some ten meter hi buck co2 pistols had for striker weights.
If your gun didn't lose any velocity with 20% off the striker,and gained shots, why not go lighter?
|This message has been edited by classicalgas on Apr 15, 2017 4:17 PM|
10m CO2 Pistols had steel strikers as standard... Except one I made in titanium
|April 15 2017, 8:42 PM |
I made a Titanium striker hammer and valve stem for a Pardini K60 CO2 pistol in the late 80s. The standard Pardini steel hammer weighed 11.25 grams, but the titanium substitute weighed 5.91 grams.
The lightweight, titanium hammer did not seem to perform better than the standard one. And to the downside, it, and various aluminum versions caused more galling problems that offset any benefits. Turns out that steel was a fine material, not to mention economical.
So, the project itself was more intriguing than the final results, because the learning experience was priceless. Turning titanium on the lathe was both challenging and fun. It required construction of a water cooling system which was the challenge. The fun? Holding 1/2 handful of titanium shavings at shoulder height, lighting it with a match, letting go, and watching it disappear before it hit the concrete floor.
|This message has been edited by MB-BOB on Apr 15, 2017 8:59 PM|
Going to retest...
|April 15 2017, 9:00 PM |
Yeah...am calling "BS" on that stock 80 shot count, unlss anything that managed to exit the barrel counts.
Relize that I may be to goal (60 shots/ 300 foot pounds/ all inside 3%) already. Using one pellet for testing kept things even along the way, but being this close, will have to try a string with heavy pellets...if the past is a guide, should be slower but earn a little more energy and likely eek out a a shot or two more.
Only two 12gr. "Match" guns I'cve had were a Hammerli Master pistol (years back...lost it in a flood 2005) and an Alfa Proj rifle.
HAd them both apart, but never got a weight on the strikers, but remeber being imprssed with how small/light they were (and as much of a PIA as it is to get that Alfa apart, I'm not likely to do it just to get the weight now).
With a bit of work, got an old Crosman 2000 (the old version...not the 2009 PCP) to manage 75-80 shots, and those are no were near the refinement of the first two.
From those three, know a single 12gr. can give (depending on temperature) 70-90 good low varation shots per 12gr.
The 20% lighter striker did work...moved the shot count up 9 shots (about 18%) with no loss in speed. So if heavy weight pellets won't get there, that's the direction I'll keep going...whittle off a few more grams from the striker, test, repeat, until I see an acutal drop in average velocity.
Good to hear from someone whose weighed real match pistol strikers, Bob.
|April 15 2017, 10:25 PM |
I note that the factory Pardini striker weighed less than half what Gub's lightened one did, but lighter yet didn't help...so maybe there is such a thing as "too light"?
I'd expect that to be the case, and I'm certain that there are differences in the energy needed to crack the valves,making direct comparisons between the two guns...iffy?
One of the principle requirements of a 10m CO2 Pistol...
|April 16 2017, 7:35 PM |
is that it be able to make 60 reliable shots (a full match) plus 15-20 sighters. Among the dozen or so 10m CO2 pistols I bought in the 1980s as part of my muzzle brake business, all of them shot +/- 100 times on a bulk fill
Shot count being so important, I surmise that all narrowly purposed 10m CO2 match pistols are designed with the lightest, most efficient strikers possible. So, anything lighter may indeed yield no measurable improvement.
Really shouldn't compare a fully developed 10m precision pistol with this general use plinker, for which sharing common parts with rifles for economy is the higher objective.
|This message has been edited by MB-BOB on Apr 16, 2017 7:42 PM|
Good stuff, this
|April 15 2017, 6:18 PM |
Is it possible that the lighter striker and same striker spring cancelled each other out? Have you thought about trying a stronger valve spring and/or lighter striker spring?
All I can say about the 80 shots per cartridge is that MY gun won't do it in stock tune, unless we're only talking about a pellet making it out of the barrel w/o regards to velocity or accuracy.
Cobalt...I've been trying lightened strikers for a few years now, and at moderate pressure
|April 15 2017, 10:35 PM |
(up to 2200 psi) I've never seen a need to push the spring strength up.
I do some mods to lower cracking effort, and sometimes to lengthen striker throw before stem contact, but I don't usually don't even fit a preload adjuster.
Running co2 in a well developed system,22 ft/lbs in .22 is fairly easy with a striker reduced 30% and a factory spring at factory preload.
Gub needs enough striker momentum to pierce a cartridge, but I run bulk, so there's another reason he might need to stay heavier.
|This message has been edited by classicalgas on Apr 15, 2017 10:37 PM|
|April 16 2017, 12:16 AM |
Thes cp1's are fun, and can be accurate, but aren't 10 meter match pistols.
Even ignoring triggers, sights, and stocking, there are different basic design features. There is more than bench accuracy at play here.
With a co2 really designed for match use (and the few that ran on 12gr.), they are designed from the ground up to be minimum power. Are designed and made to do one thing, accurately toss .177 pellets out at low speeds.
What we're doing with "sporter" designs is trying to force them into being what they don't naturally want to be.
So let me ask....if you were to design from the ground up a match pistol's internal system, just for match type shooting:
1. LArge internal valve volume or small?
2. Light striker or heavy?
3. Long striker stroke or short (which goes along with spring length and stiffness)?
I just picked 60shots/5 foot pounds/ 3% varation as a goal, and a desire for a truly quiet back yard pistol. Getting the gas use per shot down reallyd did quiet it down even more (shrouded); not losing any energy was kind of a bonus.
I bet it could be done
|April 16 2017, 1:48 AM |
lighter hammer, lighter springs, and less movement from the shot cycle.. An LW barrel from a crosman, carving the grips to fit the hand, getting the trigger down to 3-4 ounces.. Installing match sights, the list goes on.. the gun would have very few stock parts.keep in mind the skanaker actually shot close to 600 fps with wadcutters.
|This message has been edited by robnewyork on Apr 16, 2017 1:51 AM|
My philosphy for any gas gun is to meter primarily with valve dwell, so
|April 16 2017, 11:30 AM |
for me, the match/sporter distinction is small at the valve construction level.
I wouldn't strangle the port or minimize valve volume, but I would use the lightest striker (and longest throw) I could make work.
I've found that a little more throw(less than 1/8" over stock) means a faster valve opening and less jounce to the gun (compared to a slightly heavier striker to get the same velocity)You get to keep the spring very close to stock levels that way, which has it's own benefits.
I'd expect the lower limit on striker weight using cartridges would be getting a good pierce in the first shot or two.
Fixed piercing nipple....
|April 16 2017, 11:47 AM |
..so they pop open a 12gr. when you screw the end cap down (and compress it to a seal at the same time)...no valve stem piercing pin.
Expecting middle 80's this week...probably 90's in the shop (being closed up through most of the day), so will get back to it once I see how it reacts with the temperature/pressure increase.
Fixed nipple...that takes care of that issue. Yeah, high temps may
|April 16 2017, 2:03 PM |
push a light striker into valve lock territory.
Stronger valve spring
|April 16 2017, 11:47 AM |
"I've never seen a need to push the spring strength up"- is this regards to the valve spring (not striker spring)? Thanks for your input as I'm new to this.
My bad, Cobalt. I keep the valve closure spring light, so that
|April 16 2017, 2:01 PM |
gas flow is as large a percentage of valve closing forces as practical (I try not to go so light that a gun has to be cocked before bulk filling, though it happens)
With the gas dynamics driving valve closure, the gun self regs better, so co2 guns are less temperature sensitive,and give more consistent velocity strings. PCP's hold tighter velocity variations and may give a longer sweet spot when a valve has good self reg ability.
It is possible to get the two springs and striker weight so far out of balance that the gun will go into serious valve bounce, and burp itself empty. There are often other factors(port size,stem leaks, poppet head size and shape, and seat area) in play as well when a gun burps.
I try very hard to avoid increasing striker spring strength,there are too many downsides to that approach, and little advantage in most cases. Increased cocking forces (and risk of increased wear and damage to the parts involved) gas use out of proportion to the power gained(too much dwell)noise, refrigeration effect in co2 guns leading to velocity swings...the list goes on.
You have her humming along beyond what I'd have thought possible
|April 15 2017, 9:19 PM |
Almost all my Co2 pistol fiddling has concentrated on souping them up for greater power, but your 59 consistent shots at 500+ FPS is way better than I would have imagined. Good job.
Like Scot, I'd be curious how an even lighter striker would behave, but I doubt it would do any better. I agree with him that it could be more prone to valve-lock issues in higher temps. I've had 2 Pardini K60's and an FWB Mini 2 that were sadly inconsistent in temps as low as 80 degrees; sometimes to the point of utter uselessness. I suspect light strikers at least partly to blame.
Hi gubb, That's really good results. I'm guessing the pistol and rifle valves
|April 16 2017, 8:49 AM |
are similar enough, that the same mods could improve the rifle performance as well.
Same so far as I can see...
|April 16 2017, 9:27 AM |
..and pretty much the same tuning has been working. I didn't sleeve the valve on the rifle, hoped the long barrel could use the "extra" gas and wanted higher energy.
Keeping the same 3% requirement, and also looking for 300foot pounds per 12gr., ended up with 34 shots / 10.3gr. / 610fps...which works out to about 290 foot pounds per 12gr. Will work on that as the weather warms (thinking for this one, 30 shots at 10 foot pounds would be useful).
Thinking on the 300fpe per 12gr. goal...it's not unreasonable.
|April 17 2017, 8:26 PM |
I were to really make a match grade co2, would follow the lead of the last of real match co2 pistols.
Would use a "smallish" bulk fill tank becasue of weight issues. Would be dertachable/standard thread refillable. Gas would be in direct contact with the metal of the tank, so it would warm back up from self-cooling quickly (10 meter shooting is normally in an eviormentally controled space).
Would be "bare barrled" so the exiting co2 gas wouldn't have a 2nd pass at cooling the barrel. Besides, a 4-5 fpe .177 really isn't all that loud and the less "crap" hung on the barrel the more natural the vibration cycle.
Keeping to match speeds, woud use a lite striker, short stiff spring, and a short stroke. Not only would that provide the match type speeds, but likely produce less vibration/weight shift inside the pistol during the shot.
Anyway....the best of my 12gr. guns is an Alfa Proj, bought used, and shortly after my wife saw it/hefted it, she "claimed it"...so it's hers now. Not really a full match rifle (it's too light and the adjustments of the sights/ stock aren't "fine" enough)...but close enough.
(No blame to her...there is something about this little slim rifle that does to women...every time I've left it out, a woman has always been the first to ask about it...why? Not really sure.)
Odd 12gr. The 12gr. cartridges fits into the pistol grip upside down...it's pierced by the bottom end cap...co2 gas has to run into a very small pressurized tube, up though a tiny opeing, and into the action.
At frist, I'd have thought that the upside down piercing of the 12gr. would promoted liquid co2 injection. But the convoluted path it takes pertty much preculdes that ever happening .
"They" (the makers) do provide a bulk fill option....but I've only used it once or twice.
With one 12gr., in warm weather, have managed 85 shots at 4.2 foot pounds (ok...that's an average of several pellet weights in this test).
The long rectangular barrel cover masks the shorter barrel. MAY not have been dseigned as such, but it makes a prtty goof (large volume)single shamber shroud.
Whic still works out to (85X 4.2) 357 foot pouds per 12gre. (which can be anything from 10.9-11.9 grams rather than 12).
LESS accurate, is an old Crosman Clallenger 2000. Has been much adjusted.made over/poilished. trigger tuned, but still runs on the original parts).
WAY less refined than the Alfa (but as my wife took the Alfa, it's the "best" single 12gr. shooter I have that I can call "mine"). Will do 75 shots (on a single 12gr.) at 4.5 foot pounds.,,sometimes gets up into the high 80's..but this is more typical.
So that's 4.5X75...which is 338 foot pounds per 12gr.
Before you "fuss at me" about the groups...both shot with the sights you see in the picture (although under bright daylight)...so "match" sights, old-guy eyes.
They only "trick" to shooting a single 12gr./ non-tube filling co2 has been to GO SLOW...has to reach some kind of equlibrium between the pace of shooting (which is the the self cooling feature of co2's gas-to-liquid conversion) and the exernal heating to ambinat temperature.
I do know more than that shot count is possible.
With enough fiddling around, time, effort, know that "sporters" can reach or exceed that shot count/energy level per 12gr.
Worked on a sinple Fusion. Striker weight.striker spring tesnion, transfer port were all "fiddled" with. While I do hate the variable nature of the accuracy, it does give a pretty good shot count (ofr 2X12gr.)
But the 760 foot pounds for TWO 12gr. works out to 380 foot pouds per ONE 12gr....which qouls be rate if I could really count of the rifle not to shoot like crap every 2nd or 3rd time I took it out).
Lastly is a 5mm QB conversion, also running on 12gr. (2X 12gr.). Not as "weak" as the others, looking for more like 12 foot pounds, and it might do better in warmer weather.
Only 52 "good" shots, but at 612 fps/ 11.8 fpe per shot, that works out to 320 foot pounds per 12gr.
So I really do not think that, at least between 4 and 12 foot pounds of energy, that 300 foot pounds per 12gr. is not an unreasonable goal to ask of a 12gr. shooting pistol or rifle. Can certainly get more shots (at less energy) or more energy (at fewer shots).
But to me, it's the goal-line...300fpe for one 12gr...600fpe for two. Can boost power up if you care to, but it you manage 20 foot pounds per shot, I'd want 15 shots per 12gr.
|This message has been edited by gubb33ps on Apr 17, 2017 8:28 PM|
|April 18 2017, 11:40 AM |
the alpha looks friggen awesome , thats why people ask!