I have an aa 500 in 177 completly stock.starting at 3 bars it has a 200 fps power curve from 820 to 1020 back to 820 at around 50 shots. do you think i need a new hammer spring.i don't want to install a reg at this time.thanks for your suggestions.
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aa 500 power curve
- Thread starter r1d2
- Start date
Please clarify if you meant to state 300 BAR and not 3 BAR. Also, at what pressure was the rifle at when it dropped back to 820 FPS after the climb and what power level? (low, medium, high?) If you did mean 300 BAR, The S400 is not designed to operate at that pressure level as the hammer and valve spring tension is not mated to that kind of pressure. That is why you have such a sharp rise in velocity.
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I see that you say it is the AA 500 though I see there are more than one version of that rifle. Which one do you have and what fill level in bar or psi do they recommend. Bill
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G
Guest
Guest
Did you buy the gun new or used? In .177 you should be getting 880fps with 10.3gr pellets with the power wheel a bit past half way. Your string should look something like this. http://airgunnation.dev/topic/shot-string-from-my-aa-s500-extra-fac/
If not then there certainly is something going on.
If not then there certainly is something going on.
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I got the gun from a good friend,it's about 2 years old.the gun had not been shot very much before i got it.i was testing with crosman 7.4
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G
Guest
Guest
The 7.4's point to why the speed was so varied. what. Was the gun stored with full pressure? I ask because the valve poppet can, but not always deform over time when stored under full pressure, causing inconsistent seating from shot to shot. Also I've tested crosman pellets in mine, just the domes not wadcutter, but they varied greatly in shot to shot consistency over the chrony and in grouping. I believe it has something to do with the hardness of the pellets and their oversized heads. Anyways i think with your new spring and a better pellet, JSB or AA you will find no faults with the rifle.
Please don't feel overwhelmed by my questions. Take them one at a time if you test for and answer and just have fun with your gun. I shoot in Field Target and Benchrest so I'm always looking for the best out me, my gun and it's ammo. That doesn't mean you have to or need to.
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I haven't had time to do a shot string yet,i have to go out of town for the weekend,will try to do a shot string monday.i will test with crosman 10.2,these shoot really well in my gun,i was testing the crosman 7.4 just because they don't group well.thanks for the help.
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Shot a 40 shot string using the cardboard box crosman 10.2 domed pellet,started at 200 bar and ended with a little over 150 bar.894,886,882,900,919,896,913,910,908,902,908,909,920,912,923,928,918,925,934,932,927,935,926,936,935,947,941,939,941,953,940,957,966,956,960,970,960,967,968.didn't have time to shot anymore.hope this enough info,so what do you think.
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Entering your data onto my spreadsheet, it is obvious that shot 33 (at 966 FPS) is the region at which your gun's optimum power curve begins at, if say, you can accept at least a 20 FPS spread. By the way, I counted 39 shots, not 40 like you stated. Anyway, you need to check at what BAR this velocity begins at then fill your gun to that pressure. If you only continued shooting past shot 39 we could see what shot number the best part of the curve ends and therefore determine how many shots you can get at this accepted velocity spread.
Referring to the illustration below, it is clear that at 200 BAR your rifle's hammer is unable to fully open the valve and overcome the pressure like how it is able to do so on whatever pressure it is at the apex of the curve; basically, your gun's hammer spring tension is experiencing valve lock at 200 BAR.
Referring to the illustration below, it is clear that at 200 BAR your rifle's hammer is unable to fully open the valve and overcome the pressure like how it is able to do so on whatever pressure it is at the apex of the curve; basically, your gun's hammer spring tension is experiencing valve lock at 200 BAR.
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99% of all the older AA 400/410's ( and my friends S500) seem to like 2,700ish psi start fill. In the AA410 ( in the classifieds by the way) fills to 2,750 for 30(+) "good" shots at 19.9fpe in .177 w/heavies Also sometimes it is a nice idea to clean & light lube the rod the hammer/stricker slides on.
John
John
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Thanks for the good info,would you suggest that i need a heaver hammer spring or should i go for a reg.if i had a reg set to 150 bars could i expect to get 50 shots with no more than 10 fps varation or just leave it alone and fill to about 170 bar.i just shot for fun and pest control.
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I have an s510 in . 22 cal. fac. at 28.5 foot pounds with jsb 18.1 I'm getting 45 shot. this is with a 30 fps spread.
I can set my gun to 36 foot ponds with these pellets but I get 15 extra shots by lowering the power to 28.5 foot pounds.
I can set my gun to 36 foot ponds with these pellets but I get 15 extra shots by lowering the power to 28.5 foot pounds.
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Putting a regulator in the Air Arms guns is a lot more involved than other guns because there are no hammer adjustments. I put one in my S500 Carbine and it turned out great, but had to lighten the hammer in a lathe and modify the firing "pot". They have a heavy hammer and a lot of force behind the hammer. You really have to reduce that force a lot when fitting a regulator.
Try setting the power adjuster halfway, fill to 2700psi, and shoot a string with heavy pellets. These are very simple and reliable guns, I seriously doubt anything is wrong.
Also try some JSB pellets. The Lothar Walther barrels love these. The Crosman pellets are so hard and don't usually give good consistency in mine.
Try setting the power adjuster halfway, fill to 2700psi, and shoot a string with heavy pellets. These are very simple and reliable guns, I seriously doubt anything is wrong.
Also try some JSB pellets. The Lothar Walther barrels love these. The Crosman pellets are so hard and don't usually give good consistency in mine.
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While it's true that the S410 is limited in power adjustability when a regulator is installed because unlike some guns it does not have an adjustable hammer spring mechanism, it's safer to change the hammer spring than shaving weight off the hammer. Once you've removed material from the S410's hammer you cannot add it back. It is better to just change out the hammer spring and/or (or both) valve spring to one that provides your desired power output and consistency. Also, the spring is easily replaceable, as in you don't need to get one directly from Air Arms. You can get it from your local hardware or specialty store.
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That's true, but the lock time becomes noticeably slow, and it encourages hammer bounce. By lightening the hammer, you decrease lock time, reduce hammer bounce. FYI, you can take as much material as possible off the hammer, and it still has too much strike for a regulator set at 120BAR. You still have to cut a coil off the hammer spring to get the hammer energy down enough to not waste air.
I've tried it both ways, and lightening the hammer is the more efficient way to do it. There is no worry of taking too much material off, because you can't make it too light in this application.
I've tried it both ways, and lightening the hammer is the more efficient way to do it. There is no worry of taking too much material off, because you can't make it too light in this application.
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