Predator Polymags w/o the tips

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marcella69

marcella69

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Oct 31, 2016
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I'm interested in any guidance out there in the performance of Predator Polymags .30 cal. with the tips removed so they will fit in my FX Impact .30 mag. I am currently using JSBs. I am pleased with the accuracy, but am looking for more stopping power as the JSBs typically just pass through game. I swear I had more stopping power with my .22 P-Rod shooting the Polymags!
 
I can't speak for .30 cal polymags or the impact magazines but the polymags don't fit in my magazines either. What I do is use a pair of fingernail clippers and snip the tips off. Accuracy does not seem to be effected out to 60 yards. I purchased these for shots less than 40 yards while hunting. At this distance, there is no change in accuracy.
If memory serves me correctly, the idea came from southergunner (youtube).
 
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I have shot a half dozen tins of Polymags through my gen2 .25 Marauder and haven't had a single issue. I am using 4 different mags too. I shoot them in my 17, 20 ,22 and .25 cal rifles and pistols. I love the way they expand. Except for the JSB Kings, they have been one of the most accurate for me. I have only found 1 red tip in the bottom of an empty tin. The Metal mags on the other hand seemed to be a 50/50 on loosing their tips in the tins. Haven't worked with any .30 calls ones. 
 
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Plinkster, the 30 cal Polymags with the tips totally removed fit and fire just fine in my Impact mag. In fact, I get a BC of 0.042 with them. That's a marked improvement over the BC of 0.022 of the JSB Exact 50s.

I have not yet field ranged the Chairgun numbers; I plan to do that tomorrow. The numbers look real good, though. Compared to the JSB Diabolo Exact 50s, I'm getting 40 more yards on my reticle (out to 158 yds) with 30.1 ft# at that range (up from 20 ft#). The hollow points of the Polymags will certainly deliver more energy into the animal than the domed JSBs. If the accuracy is commensurate with that of the JSBs, I found my new pellet!
 
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Maybe someone can explain this to me: When I adjusted the Valve Control Knob on my FX Impact .30 from two long lines showing to two short lines showing, which I thought would increase power; I lost a couple foot pounds of energy, but almost halved the SD! I'll take that any day :)

1n1gng.jpg
 
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"marcella69"Maybe someone can explain this to me: When I adjusted the Valve Control Knob on my FX Impact .30 from two long lines showing to two short lines showing, which I thought would increase power; I lost a couple foot pounds of energy, but almost halved the SD! I'll take that any day :)

1n1gng.jpg
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Pretty easy to explain :)
The valve control contains a rubber ball which acts as a mechanical end stop for the main valve.
When the end stop is turned out all the way, the valve does not, or barely makes contact with the end stop, allowing the valve to open a wee bit more or less every time you fire a shot. (A hammer never strikes with the exact same force every time.)
When you turn in the VC knob, the ball acts as a bumper for the valve, thus creating a more defined (more precise) valve stroke. It's this defined valve stroke which will decrease both your ES and SD.
 
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weatherby, wait a minute. I get that increasing/decreasing velocity sometimes can improve SD by making the pellet more stable in flight, depending on the pellet type. But when I turned the valve control knob out, it reduced velocity. I thought that turning the valve control knob out increased velocity (within margins), per se. (The setting I have now is merely the factory setting.) Am I to understand that the combo of the power dial, reg pressure, and power control knob is a gestalt; and therefore would explain that turning the power control knob out can, in some instances, actually reduce power? Keep in mind that AOA tuned my reg pressure to be higher than factory: 145.9 bar, and I keep my power dial set at MAX on my FX Impact .30. At any rate, thanks for the feedback.:)

One of these days I'll dig deep into the specs and physics of the deal; but since I have somebody whose brain I can pick, I figure I'll take a short cut!
 
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So, in your case it acts the other way around, that's indeed not exactly what someone would think ☺
It looks like it has got something to do with the free floating hammer of the FX guns.
I've written it as advice in many other threads as well, as people tend to max out the HST on their FX to get the highest possible velocity. We'll, to be short, it isn't ☺. 
There is a way of diminishing returns here, when you start to increase the HST on any FX, eventually the speed will drop instead of rise, while the air consumption gets horrible.
In your case, it seems that the rubber ball is preventing the valve to overshoot it's optimal setting, hence the increase in speed.
Just as a sidenote, leaving the HST on max. and turning in the valve control too much doesn't really sound good for the rifle. The hammer is smacking the valve at full force, while the valve can barely open because the valve control knob is blocking the valve stroke. It seems better to also decrease the HST setting slightly when turning in the valve control knob in pretty far. 
With this specific FX phenomenon in mind, you can also try out if your speed increases with the valve control all the way out, and your HST set at a setting lower than MAX :)

regards,

Gijs 
 
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Hi all. I've read all a can about settings ect with the fx impact but I've never understood exactly what was going on with varying HST until now. I knew it was happening but not why. Why more HST tension can decrease velocity. So basically if I understand correctly the least HST to achieve max valve travel will ensure the valve is open for max time. Also winding out the slack in the power wheel could actually compound the issue on max setting. 
Sorry for jumping into the middle of this conversation but been following and I've learnt something new. 
Cant wait to get chrony out and see if I can get the .25 heavies travelling a little quicker and more stable. 
Marcella69 hope this works for you and Gijs thanks again for explaining this. 
Shame you didn't get some input into impact owners manual!!
Michael
 
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MousefartWe've drifted pretty far from this being a Polymag thread, yes?

Back on topic, I have a confession. I must be the last person on Earth to have learned this: I discovered yesterday that they won't chamber in a .25 Wildcat. So THAT is why everyone is cutting the tips.

Doh!
Click to expand...


True, but to be honest, this thread is about .30 polymags, not .25 ;)
Sux that they don't fit a lot of magazines, they are fine pellets for sure.
 
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I suppose that everyone has me to thank for the original topic (which I started!) going astray; I keep adding new twists on the theme!

AirSupply, I must admit; I'm still pretty cloudy on the dynamics vis-à-vis the power wheel ("PW"), the valve control knob ("VCK"), and the reg pressure ("RP") on my FX Impact 30. All I can say is that I'm happy with the settings I have (PW: MAX; VCK: Two short lines showing; RP: 145.9 bar). Shooting the Polymags w/o the tips (back on track!); I am getting 72.88 ft#, an SD of 3.02 (the lowest I've ever had w/ my Impact), and a BC of 0.042 (almost twice that of the JSBs).I think I'm done tinkering for awhile (unless somebody comes out with a better hunting round for the 30 cal.)
 
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weatherby, I really appreciate your studied analysis of my situation. I am gaining insight into the dynamics involved. It is great to actually understand the engineering and physics involved (and I will continue to try to), but the bottom line is that I'm tickled pink with the performance of my Impact at this point. (See my reply to AirSupply's post.)
 
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