Maximus shot string Chrony values

[addertooth]

I put the Maximus across the Chrony yesterday.  The results are not surprising, but are worth posting for general information.  Keep in mind every air rifle exhibits characteristics which are unique to that rifle.  Some may be a lower power, but achieve more shots; others may have more power, but fewer shots.  The hammer, transfer port and valve are stock on this Maximus. 

Air Rifle: Benjamin Maximus 2016 model.
Pellet: H&N 14.66 grain Field Target Trophy 5.53mm. No pellets were loose in breech.
Chrono used: ProChrono Digital
Conditions partially overcast 73 degrees F.  Outside. 
Chrono String 4
high velocity shot 868
low velocity shot 742
average velocity of all shots 830
extreme spread 126 (868-742)
standard deviation 39 (Large due to continuing string past the cliff).
Starting pressure 2000 PSI, but guage may have error.
Maximus shots put in order from shot 1 to shot 33
854 shot 1, bell curve begins to rise here.
860
859
862
864
867
858
865
866
864
868 Shot 11 peak of bell curve.
865
861
859
858
855
850
844 *First shot below 850 fps, shot number 18
839 *cliff seriously begins here.
834
828
823
817
809
805
796 *First shot below 800 fps, shot number 26
788
784
775
768
760
751
742 *shot 33 guage reads 1000 PSI, but may be off.

[rsterne]

Looks like 20 shots within a 4% ES.... not too bad, IMO.... a very slight decrease in hammer spring preload would increase that....

Bob

[addertooth]

You nailed it exactly Bob.  I also feel like it is essentially a 20 shot rifle.  The maximus does not have an factory adjustable hammer, but if it did, lightening it to about 20 FPE would be about perfect for me.  Perhaps a heavier pellet might give me a slightly higher shot count as well.  Some JSB's are on my heavier pellets to order list.

[RobertMcC]

You nailed it exactly Bob.  I also feel like it is essentially a 20 shot rifle.  The maximus does not have an factory adjustable hammer, but if it did, lightening it to about 20 FPE would be about perfect for me.  Perhaps a heavier pellet might give me a slightly higher shot count as well.  Some JSB's are on my heavier pellets to order list.

I just opened mine up and noticed this.



Right what came out of my gun that gave me 30 shots at like 19-20 FPE, Left is a Disco hammer spring.

With the disco spring I got about 13 over 800 and only 17 all together from 2K to 1K.

[Tater]

Good post Todd. Thanks for showing the stock shot string. I'll be doing similar testing with mine soon, and probably bump up the power a bit for a flatter trajectory and being able to try heavier pellets. Right now it gets about 35 shots starting at 720 fps or so using JSB 15.89's.

[addertooth]

RobertMcC,
Odd, I get 25 shots over 800 fps.  But like I said, each rifle is a bit different.  Perhaps my transfer tube has a couple less burrs in it.  Quite possibly you are shooting a heavier pellet (JSB 15.89?)
It doesn't drop below 20 FPE until shot number 29. (784 fps, with 14.66 grain equals 20.01 FPE). 
I suspect yours has some great room for you to tweak and tune it. 
I would like to have a wimpier, or shorter spring to drop me down to 784 fps average, with a bit broader and flatter curve.
From everything that has been read, 20 FPE is more than enough for Squirrel, Rabbit, Dove, Pigeon and other small pests.

[Dairyboy]

I put the one together for Tater and I used a short stiff spring and a Mellon air velocity adjuster. It can be cranked up to quite a bit more power and also backed off to very little power. How I set it up is also very efficient and stopped hammer bounce (from what I could tell and the consistency of the string was extremely good. My first suggestion is either clip the spring or get a Mellon air adjuster which can tune it a very wide variety of ways and if wanted to change a spring don't need to tear the entire gun apart for.

[addertooth]

I took a peek at Mellon's website.  Seemed a tad unfriendly... don't ask me questions, I don't make recommendations... blah blah blah.. Is it the adjuster for the 22XX series 7/8ths in steel you used?

[Tater]

I put the one together for Tater and I used a short stiff spring and a Mellon air velocity adjuster. It can be cranked up to quite a bit more power and also backed off to very little power. How I set it up is also very efficient and stopped hammer bounce (from what I could tell and the consistency of the string was extremely good. My first suggestion is either clip the spring or get a Mellon air adjuster which can tune it a very wide variety of ways and if wanted to change a spring don't need to tear the entire gun apart for.

I just love how it's set up too. Thanks again Dillon, it's a fantastic shooter. I'll probably turn it up some, but it shoots so nice (and accurate) now that I hesitate to change anything.

[RobertMcC]

I took a peek at Mellon's website.  Seemed a tad unfriendly... don't ask me questions, I don't make recommendations... blah blah blah.. Is it the adjuster for the 22XX series 7/8ths in steel you used?

22xx PA will work with the maximus.

[Dairyboy]

I put the one together for Tater and I used a short stiff spring and a Mellon air velocity adjuster. It can be cranked up to quite a bit more power and also backed off to very little power. How I set it up is also very efficient and stopped hammer bounce (from what I could tell and the consistency of the string was extremely good. My first suggestion is either clip the spring or get a Mellon air adjuster which can tune it a very wide variety of ways and if wanted to change a spring don't need to tear the entire gun apart for.

I just love how it's set up too. Thanks again Dillon, it's a fantastic shooter. I'll probably turn it up some, but it shoots so nice (and accurate) now that I hesitate to change anything.

Glad to hear that Jerry! I'm always hesitant to do the same thing on mine but you should be just fine turning it up some!

Yes the 22xx size is what you want. I went with the aluminum but the steel will work as well

[addertooth]

Thank You both for the answer on the part from Mellon's site.  I struggle to decide whether I want to throw more money into the Maximus, or simply purchase the Marauder.  The decision has not been made yet, but I am leaning towards just getting the Marauder.