In appreciation of BigEd's work

In appreciation of BigEd's work

Joined: July 24th, 2009, 4:33 pm

June 16th, 2012, 6:12 pm #1

My B50 is a hot little chili pepper. I've chronographed it tossing 18.13 grain JSB Jumbo heavies at up to 998FPS. I've tried many things to calm it down. I do a lot of testing in my basement. Down there the rifle is in an enclosed space, of course. It's as loud as a 22lr too, of course. Well I finally did something about that. I've installed BigEd's shroud and riser kit. The wife has noticed a huge difference (from the top of the stairs). My ears have too. This kit is very effective. Installation is quick. I took 25 minutes from removing the scope to replacing the scope. All parts fit perfectly, and this level of workmanship is really appreciated. The rifle is now backyard friendly. I never would have considered that before installing this kit.

So, thank you BigEd. Keep up the good work!
darryl
a few pix:
?t=1339870159
?t=1339870194
?t=1339870233
?t=1339870265
?t=1339870347
?t=1339870297
Last edited by turbodt on June 16th, 2012, 6:14 pm, edited 1 time in total.
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Joined: January 31st, 2011, 7:14 pm

June 16th, 2012, 8:23 pm #2

congrats. now that b50 is starting to come together. It's been a long time coming!!! have you been able to tame it yet ?
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Joined: July 24th, 2009, 4:33 pm

June 16th, 2012, 11:39 pm #3

With the help of good friend Gary, and some inspiration from the Book of BAM, I've been in a seeming never-ending quest to reach my goals with this rifle. I've tried various transfer ports, and spring guides, different springs, cut oem springs, and lighter hammers. I've been reviewing the spreadsheets from all the tests I've run and chasing the (my) holy grail of tuning: a flat shot string of at least 3 10-shot strings, each with an Es lower than 20 PS, and ab Sd as low as can be managed. I've dropped my energy goal to 30 shots averaging 28 FPE. I had to take a break from tuning the 50 for a short while to make a go of some other air guns (not necessarily easier tunes). I'm ready to get back at now that my ears have quit ringing! LOL!!!
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Joined: January 31st, 2011, 7:14 pm

June 17th, 2012, 4:33 am #4

I understand the never ending battle to get it to where you want it. I wish the book about the b50 was for .22 cal instead of.177. the book works for .177 but not so good for .22- you are on your own.
that flat string seems unreachable without a regulator. I've seen the extreme spreads that range in the 80's to the mid 20's but the shot count is always bad, but the accuracy is there. I just shot for 20 shot then refill to 2500 psi. maybe one day i will just email Mr. Ed to see if he can work some magic on it. would love to see a gauge on it. keep us updated
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Joined: November 17th, 2006, 3:51 am

June 17th, 2012, 6:25 am #5

With the help of good friend Gary, and some inspiration from the Book of BAM, I've been in a seeming never-ending quest to reach my goals with this rifle. I've tried various transfer ports, and spring guides, different springs, cut oem springs, and lighter hammers. I've been reviewing the spreadsheets from all the tests I've run and chasing the (my) holy grail of tuning: a flat shot string of at least 3 10-shot strings, each with an Es lower than 20 PS, and ab Sd as low as can be managed. I've dropped my energy goal to 30 shots averaging 28 FPE. I had to take a break from tuning the 50 for a short while to make a go of some other air guns (not necessarily easier tunes). I'm ready to get back at now that my ears have quit ringing! LOL!!!
Think you can make it to 28 foot pounds/ 30 shots but it may take a bit of valve work along with some striker weight changes (that large/heavy steel spring guide).

Got something in the 195-200cc range for volume, so to get where you want to be the efficency is going to have to be pretty high...but certainly possible.

Have managed 20 foot pounds for 40 shots inside of 3% vel. variation, but as energy goes up, air use gets less efficent...and shot count doesn't stay proportional.
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Joined: July 24th, 2009, 4:33 pm

June 17th, 2012, 11:45 am #6

I've had some good results in tuning my FX Timberwolf. That was relatively easy, and gave me a fairly flat shot string with an average of 28 FPE for 36+ shots before dropping off. I'm most proud of my work with my Logun S16/.22. When I first chronographed it, the shot string looked like an incline with the each successive shot being of lower FPS. Here is that first shot string (with H&N FTT 14.66 grain pellets) and my current/best tune with JSB Jumbo Heavies at 18.13 grains:
?t=1338603137
?t=1338603310

As you can see, barely, I accepted a drop in power for more consistent power. I don't hunt, so an average of 28 FPE across 49 shots (with low ES and Sd values) is pretty good.

I know I can get similar results from the '50. Hey! Might as well be optimistic! But I agree wit you guys; difficult, but not impossible. I can accept lower energy in pursuit of the holy grail of flat shot strings and decent shot counts, but a little power is a good thing too. I've got over 40 test-spreadsheets for the B50. I think I'll go back and review them all before proceeding. Here's to luck!
darryl
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Joined: November 17th, 2006, 3:51 am

June 17th, 2012, 2:29 pm #7

..and going for whatever power will allow me 20 shots @ a low variation. Have some other lower power/long shot count .22's which has made me re-think this one's use. Will see...hope to get into it later today.
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Joined: July 24th, 2009, 4:33 pm

June 17th, 2012, 3:04 pm #8

I'll check back later to see what you've come up with. Meanwhile I think I'll spend a couple of hours to see where I'm at with my '50. luck to us both.
darryl
Last edited by turbodt on June 17th, 2012, 3:11 pm, edited 1 time in total.
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Joined: March 28th, 2002, 6:54 pm

June 17th, 2012, 5:33 pm #9

in that hot 50.Essentially a shim stock one way brake. At one point there was talk of a version becoming available from one of the tuners, but I haven't heard of it for a while.
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Joined: November 17th, 2006, 3:51 am

June 17th, 2012, 9:46 pm #10

I'll check back later to see what you've come up with. Meanwhile I think I'll spend a couple of hours to see where I'm at with my '50. luck to us both.
darryl
Kind of stuck.

Lost (or used in some other project) the original striker spring and I don't have a good replacement. The lower power one that is in there maxes out at 150BAR. Even shimmed up, sweet spot is at 150BAR. When I buy/find a replacement spring, would be able to either get more power...or by adding that new spring and then strangling off the transfer port slightly, the same power as now and a longer shot count.

Also did not find the original top hat (the spring guide that fits into the striker). Found a lighter version (not ultra light, just spool shaped so its about 15% lighter).
[/IMG]

The odd thing is the stroke adjuster. As expected, shortening the stroke lowered speed and lengthening stroke increased speed. BUT, past about the middle point, speed decreased as stroke increased. Really not sure why.

Anyway, after a half dozen disassembles and changes, here is where I leave it for today:

[/IMG]

BAM 51
10X42mm 30mm tube
21gr. Baracuda
150-110 BAR
5 shot/25 yards

String:
785
785
788
786
785
787
789
794
800
800
806
810
809
806
807
800
803
800
801
794

Average: 798 / 29.7foot pounds
Works out to a bar-cc/fpe of about 14

(In case you are wondering, 14.3gr pellets average 922fps).

Which isn't real impressive. Thats only 20 shots inside of 25fps.

But it shoots decently well:
[/IMG]


So I'm thinking (in terms of your project):

If I can get the sweet spot up 25% to 180-185 BAR (new spring and a heavier top hat) and the efficiency a little bit better (10%) might get close to 28 foot pounds/30 shots.





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