Today reader RidgeRunner continues testing his .25-caliber Benjamin Armada. If you’d like to write a guest post for this blog, please email me at blogger@pyramydair.com.
Take it away, RidgeRunner
Tuning my .25-caliber Benjamin Armada: Part Three
by RidgeRunner
My Benjamin Armada as it is currently set up.
This report covers:
- At the range
- Started with the hammer adjusted short
- Naked gun
- FX 25.5-grain pellets
- JSB King Heavy MK II
- FX Hybrid 26 grain slugs
- Fully clothed
- Next time around
- At the range
At the range
On the day I ran this test it was pretty hot. OK, fine. I thought I would first give the .25-caliber Benjamin Armada a try with the hammer set on maximum spring tension and the striker adjusted all the way back. That would give the hammer maximum travel before it hit the valve with all the energy this spring could give.
I asked RidgeRunner what the difference is between a hammer and a striker and he sent the following to me.
“They are two separate parts on the Marauder/Armada. The spring works directly on the hammer. the striker screws into the end of the hammer and can be lengthened. it is also the face of the hammer that strikes the valve.”
That means the striker is a part of the hammer that adjusts, lengthening the hammer’s stroke. Indeed, in the Armada manual they are referred to separately!
I was shooting at fifty yards on this day with the Armada resting directly on my shooting bags. I shot eight-shot groups again as eight pellets are what the .25-caliber Armada magazine holds.
Started with the hammer adjusted short
Now the whole truth is I first tried to shoot with the striker adjusted all the way forward. That means the hammer travels the least distance before hitting the firing valve. After a few pellets landed in the dirt, I decided to adjust the striker back all the way for maximum hammer travel. Much better!
Naked gun
Another thing I did was to shoot the first three groups without putting on the forward rails and the bipod. She was almost naked. She shot pretty good that way, as well.
The rifle without the forward rails and the bipod is what I call a naked airgun.
FX 25.5-grain pellets
The first pellets I tried were the 25.4 grain FX pellets. Eight of them went into a group that measured 0.907-inches center-to-center. Not too bad. Better than last time.
The Armada put eight 25.4-grain FX pellets into 0.907-inches at 50 yards.
JSB King Heavy MK II
Next, I tried out the JSB King Heavy MK II pellets. Eight of them made a group that was 0.569-inches center-to-center. Now we are starting to talk!
The Armada put eight JSB King Heavy MK II pellets into a group measuring 0.569-inches between centers at 50 yards. Yes!
FX Hybrid 26 grain slugs
I wanted this to be my slug gun so I decided to give FX Hybrid 26-grain slugs a try. At 50 yards eight of them made a group that measured 1.219-inches between centers. I am not impressed. Maybe I will have to use a heavier swaged bullet.
The Armada put eight FX Hybrid 26-grain slugs into 1.219-inches at 50 yards.
Fully clothed
Next, I put all the parts back on the Armada and shot the 25.4-grain FX pellets again to see if there was a real difference. This time eight pellets made a group that measured 1.713-inches, center-to-center.
The Armada clothed with the two side panels and the bipod.
With the side rails and bipod back on the Armada shot eight 25.4-grain FX pellets into a group that measures 1.713-inches between centers.
Next time around
I have my doubts about whether the Armada shoots better with or without the front rails on her, so the next time around I will dive deep into that and find out. If she does shoot better without all that stuff on her, those front rails will end up in the spare parts bin and she will be allowed to dance almost naked.
Note from BB
I enjoy this series from RidgeRunner because it illustrates all the things that happen as we test an air rifle with certain pellets. You guys see me do this all the time. In this report you see someone who doesn’t do it all the time, and that looks more realistic.
RidgeRunner,
I know you shot it initially using domes to get a baseline but you haven’t done any shooting over a chronograph while using slugs to determine how fast those slugs are going as far as my rememberer tells me. If the hammer is already adjusted as far as it will go how will you get more velocity if you need it? How fast do slugs have to go to demonstrate accuracy in other guns?
Siraniko
Siraniko,
I have not shot the FX “slugs” (cast/swaged bullets) over the chrony yet. This is my first experience with them. As far as more power/velocity is concerned, this is all I get. I can and likely will play around with diameters and weights a bit, but I am not expecting too much more from this air rifle. I was getting more accuracy from a heavier pellet. Maybe a heavier “slug” will give me better accuracy also.
Velocity is not what gives you better accuracy. When I was helping/shooting with my father in my powder burner days, we did not load the .25-06 to the maximum load. We used a lower/slower load to achieve the best accuracy (1/3 MOA).
RidgeRunner,
I get it that velocity does not equal accuracy. I was actually thinking if the velocity gave enough spin to the projectiles from the rifling to give them stability during flight.
Siraniko
Siraniko,
Unless I am mistaken, the velocity has nothing to do with it. The twist rate is what provides the spin that will stabilize the projectile. This is the reason why there are so many different twist rates for different length and weight projectiles, not just for airguns, but powder burners also.
The “standard” of 1:17 twist rate is really a compromise. This is one of the reasons for testing of different pellets. The HM1000X I had used a different twist rate than this. The FX Impact uses different twist rates for their pellet and “slug” liners.
RR
Sorry to be so long in responding. Been in the hospital all last week. Got out today and the first thing I did was go to this blog. Dedication or obsession?? anyone’s guess.
Anyway, I believe you are mistaken. When you increase the velocity of a bullet or pellet, it travels through the barrel more quickly. The 1 turn every 17 inches forces the projectile to follow the lands and grooves and so the faster it moves those 17 inches the faster it has to turn while doing so.
Consider a barrel with a 1 in 12 twist. If the speed the projectile travels through it is 1000 fps, then it will have done so in 1/1000 of a second. or 1000 revolutions per second. If it was only traveling at 500 fps, it would have taken twice as long to leave the barrel and done so in 1/500 of a second,, or 500 revolutions per second.
For any given power level, every change in projectile weight will invariably change its rotational speed. This “could” explain why some guns like certain weights. But none of that explains why two virtually identical guns shooting the same pellets don’t achieve the same results.
I had a model 70 in .270 that would shoot my handloads into cloverleafs at 100 yards. I tried quite a number of loadings but got the best groups using compressed loads of 4831 powder (no longer produced as far as I know). Now I could use a faster burning powder to get more velocity, but after many hundreds of rounds, found that old military powder did the best for me.
I didn’t own a chrono back then, so I had to estimate velocity by how high or low my shots were.
Sorry I got windy, there.
Ed
edlee,
Long winded and on topic is no problem here. Long winded and off topic is not a problem either as long as it is family friendly. If you have read some of the comments of the past they were twice the length and very far from airguns. Glad to hear you are out of the hospital and hopefully in better health.
Siraniko
Thank you,, now if I can just stay out, all will be well.
edlee,
I may be wrong and you may be right. My thinking is no matter how fast a projectile moves, it will be rotating a given amount over a given distance. Certain projectiles require certain spin rates to stabilize properly, however velocity also is a factor. Too slow or too fast and accuracy goes out the window.
RR
It’s all about how fast it is forced through the rifling. Once out of the barrel, the spin slows. The rotational speed slows less than the velocity does,, but it still slows.
My point was the rotational speed as it leaves the rifling and that is definitely dependent on how fast it is going.
Lots of other stuff happens that affects accuracy. good equipment maintained properly help with that,, but as I can testify from my own experience, the human factor is likely the single biggest factor.
Wow, nice shooting at 50-yards! Those JSB King Heavy MK II pellets might just be the ones this gun likes the best. Are you still loading the pellets one at a time? Or are you using the magazine now? Looking forward to seeing if the front rails make a significant difference in accuracy or not.
Elmer.
He is still shooting single-shot. He just shoots eight because that’s how many .25-caliber pellets the magazine holds if he was using one.
BB
Elmer,
I am also curious if the front rails have any affect. We shall see.
The group using JSB King Heavy is approaching 1 MOA. Not too shabby, uh.
Accuracy or lack of it with the rails and bipod attached is interesting for sure. Just how hold sensitive is this pneumatic?
Is an adjustable length hammer yet another variable to add to the mixture of tuning possibilities? Is this the only airgun that has this feature or is it common?
Good report.
Deck
Deck,
I for one do not know if the “other” airguns use an adjustable length hammer as this one does with the exception of the Marauder. Does the SAM use it? I do not know.
This also does not have a regulator as so many of the “new” airguns do. Like I and others have stated before, unless you are shooting a geegob at targets, you do not need one.
I do not think the rail is affecting accuracy as with and without such the barrel/shroud is free floating. I will be running another 50-yard test with her fully dressed and maybe even out to 100 yards.
RidgeRunner,
Marauder and Bob Sterns’ Hayabusa project.
Lots of custom airguns.
shootski
Deck and RR, if you watch the video that BB linked to in part one of his Challenger reseal report, I think you can see the adjustable length hammer on display. If I remember it correctly, he uses that for a coarse adjustment of velocity. Then I think he uses the spring tension for the fine adjustment of the velocity.
Elmer
Thanks for video tip. Hammer stroke adjustment is clearly shown.
Deck
RidgeRunner,
I looked for my copy but can’t find it :^l
“Lloyd’s Hammer Strike spreadsheet”
It covers most of the topic. Also: https://www.gatewaytoairguns.org/GTA/index.php?topic=144675.40
Is a good start to resources.
This was a big topic back five-ten years ago! There are SO many variables to it that it isn’t worth too much time in my opinion; especially with stock parts.
The takeaway in my opinion is balancing DWELL time and hammer/striker MOMENTUM will give best energy performance…and that is typically NOT maximizing everything in the knock open.
The FULL DUMP valve (or the no valve burst disk approach gives best Muzzle ENERGY (ME) compared to any other method. That is what the Burst Disk method taught me. With a hammer-striker how fast the valve opens gets you there. The maximum length setting of the Striker can actually reduce ME in stock guns.
Good luck!
shootski
RR,
I would assume that shooting one MOA is the objective?
PCP’s worth a darn should be able to do that, IMHO.
Keep up the good work.
-Yogi
Yogi,
I hope to do better. We shall see when all is said and done.
Speaking of Yogi, his buddy Boo Boo paid us a visit last night and carried our trash can off to the woods.
I went on a mini road trip today to pick up something for Mrs. RR.
I do hope Jeff Foxworthy will forgive me, but…
While driving, if you use your turn signal when making a turn, you just might be a curmudgeon.
While driving, if you stay within 5 MPH over the speed limit when cruising, you just might be a curmudgeon.
While driving, if you try to maintain a safe stopping distance between you and the vehicle in front of you, you just might be a curmudgeon.
Does this mean “curmudgeon” really means a sensible and prudent person? Wow! I want to be one, too!
RG,
If you live long enough, you just might become a curmudgeon.
RidgeRunner,
If i do two out of three am i a curmudgeon?
I FAIL because of my Need for SPEED. My view is that going 10+ faster than the of the Flow of traffic keeps most of the wrecks in my rear view mirrors.
I don’t cut others off and am 115% focused on driving my three pedal cars and the things happening at least a quarter mile ahead. It is Situational Awareness (NO AI systems Involvement.) based driving.
shootski
No, you fail because you are irresponsible. How many of those wrecks in your rear-view mirror were caused by your wreckless behavior.
RidgeRunner,
To the best of my knowledge i have not caused any wrecks by my driving method. I have however avoided any number of them by being one of the most attentive drivers on our highways or Autobahnen. From my driving experiences in Europe SPEED is not what kills it is INATTENTIVENESS and not following/knowing the other rules of the road.
shootski
Shootski,
We drive alike, “Drive fast, drive smooth”, no tickets. No challenge, no fun.
If someone wants to pass me while I’m driving 10-mph over, I will pull over ASAP. Let him draw out the police in speed traps. Mostly follow all the rules but speed limits were established for old ladies on a Sunday drive. How else could I maneuver a 30-mph turn at 60-mph with ease. OK a 180-mph semi-race car really helps.
Curmudgeon for being courteous (I signal when passing 5 cars at once, Ok 4 cars behind a semi tractor trailer) but arrested ‘old age’ development pretty much covers the rest. Stay young!
Bob M,
Could i drive any other way?
In the Summer: Bridgestone Potenza RE-71RS
On both my TUNER SAAB 9-5 AERO as well as the 9-3 VIGGEN both with: SS 3″ tuned Header/Pipes, Race Cat and High flow muffler.
In the Winter there are four REAL ICE/SNOW performance rated tires on each car.
In the Winter our family rule is when the first flakes start to stick we stop for coffee or a meal and wait out the ID 10 TANGO mayhem. Then we hit the roads and drive to our intended destination being careful to not hit any of the many wrecks ;^)
You stay young as well!
shootski
PS: Range Gate Pull Off works.
If your gonna do it, do it right. The Veloster N has it all built in. Just need to select driving mode and options or hit the ‘N’ mode on the steering wheel for full race mode, a really rough ride option for the street.
Flakes from the sky, I think I remember that. Been many years !
My youngest learned early and well, when she finally came to a stop, in the middle of an intersection. Driving in her first rain with her jacked up Toyota truck. Pure luck, no traffic.
“Next, I tried out the JSB King Heavy MK II pellets. Eight of them made a group that was 0.569-inches center-to-center. Now we are starting to talk!”
RidgeRunner, yeah, now you’re talkin’, for sure; I’d be pleased as punch with that! 🙂
Just looking through an Armada box and I found a replacement spring I evidently forgot about and never installed. In the plastic bag is a business card from Wicked Air Rifles, LLC with a note to self. “Hammer Spring +Power #10” and a barrel shroud extension adaptor. All I need now is another Round Toit. Washers may do the same, space permitting.
And wouldn’t you know it, I just found a Hard Air Magazine article about tuning the Marauder for 100psi more and it may not be necessary. 200psi more may not only dispatch pests but also knock them off my property?
Ex wife returned from hospital, heart failure symptoms. Drained excess water from her body, swollen legs, right lung, monitored organs for proper operation and gave her more drugs to take for life. Stay active.