Author Topic: My first PCP (Read 11488 times))

nervoustrigger · « **Reply #20 on:** January 19, 2013, 05:44:19 PM »

Okay, I ran my mouth off a few minutes ago about how accurate this rifle is. But as they say, no pic, didn't happen. I pumped it back up to 200 bar and pinned up a new target. Took me a few shots to get back in my groove but here's what it's capable of when I do my part:

Ribbonstone · « **Reply #21 on:** January 19, 2013, 08:18:56 PM »

Now you know why it is the "dark side". Hitting what you aim at is so addicitive.

nervoustrigger · « **Reply #22 on:** January 19, 2013, 10:50:41 PM »

Here's a sampling of 4 different pellets. I was really surprised at how it sprays the RWS Superdomes because they shoot well in my other two rifles. The RWS Super H-points and H&N FTT 5.53 both grouped fairly well but not like the Predator Polymags. It apparently likes those. Good for me. Bad for the nutters.

Sqrl Klr · « **Reply #23 on:** January 20, 2013, 01:46:30 AM »

Good group with the PP's. Looks like it would group well with jsb too.

aack73 · « **Reply #24 on:** January 20, 2013, 01:51:50 PM »

very nice when the polymags group well.

tobar832 · « **Reply #25 on:** January 23, 2013, 03:24:07 PM »

Jason,
Well I jumped the shark and heading for the DARKSIDE! My B-50 is on the way from MM. Been on the phone with Mike a couple of times asking questions. He sent me The Book on B-50 and frankly I'm a little worried. All the tweets and mods you can do to this gun makes me feel like I bought a Kit gun. I hope I can pull this thing out of the box, clean it, and the start pumping. You posts have given me a little insight on the B-50 and what to expect.
Keep posting about what your doing with the B-50. Maybe I can learn by your doing.

Great looking gun too. I'll post some pic's too.

nervoustrigger · « **Reply #26 on:** January 24, 2013, 08:50:22 PM »

Tobar,

Congratulations! Based on what I've seen from mine so far, I think you'll be very happy with it. Don't be worried about the book. If you're a tinkerer, then it's a fantastic platform but it shoots very accurately out of the box with respectable power so there's no need to go fiddling with it if that's not your style.

The only thing I've noticed about mine that I consider essential is rounding the edges of the loading port where the bolt passes through. Mine was eating up the little O-ring near the tip of the bolt. I don't know if they're all like that but ChrisK has a section about it in his book so I assume so.

I did clean the barrel on mine before shooting it but it wasn't anywhere near as dirty as the pile of filthy patches shown in the book.

I'm absolutely tickled with the accuracy from the JSB 15.9's. You didn't mention if you are getting a .177 or .22, but if it's the .22 then I highly recommend you pick some up.

nervoustrigger · « **Reply #27 on:** January 24, 2013, 09:07:10 PM »

Seeing as how this rifle is capable of stacking pellets at 25 yards, I stretched out to 50 yards to see what it can do. Besides a bit of trajectory drop, I was seeing about a 1" kick to the right on average. There was absolutely no wind though.

Back up a few days. I had to dial in a pretty good bit of windage adjustment on the scope to get it on target at 25 yards, and I had read that not having the scope optically centered can cause that sort of lateral shift at different ranges. They make adjustable scope mounts to deal with this sort of thing but they're fairly expensive, and with this rifle you can do it for free.

So using a mirror and flashlight, I recentered the windage (vertical crosshair). I then loosened the 3 set screws on the barrel band and gave it a slight twist and tightened them...just snug for now so as not to dig them in and scar up the tube.. This pulls the barrel slightly left or right. A small adjustment here makes a big change in the point of impact out at 25 yards. After a handful of trial-and-error attempts, I got within 1/4" of hitting my lateral mark. I snugged them up tight and dialed in just a few clicks to get it dead on.

Back to the 50 yard target. On the first try, a bit of holdover and POW, right in the bullseye. Okay, I'm a believer.

mikeiniowa · « **Reply #28 on:** January 25, 2013, 07:41:48 PM »

the reason for the don't fire unless under pressure is the small brass fitting on the back of the valve, it holds the o-ring to seal the stem. As we know brass is soft and the steel striker hitting it with no pressure will deform it to the point where it will not allow the valve stem to move, rifle will fire then the stem sticks and it dumps the whole load...complete tear down is needed to get to it and then it needs to be drilled out so the stem doesn't bind...had to fix more than one...not a big problem but a real pain in the butt to do, you will only do it once...

nervoustrigger · « **Reply #29 on:** January 28, 2013, 12:40:15 AM »

Spent some time with the chronograph today getting a shot string. The rifle has no modifications. Shot Crosman Premier Hollow Points starting at 3000psi and got 88 shots before the velocity dropped off below that of the first shot. Peak velocity was 910fps yielding 26fpe.

After the last recorded shot, I sat down at the bench and fired a test shot at a 1/4" diameter bullseye at 25 yards, though with a JSB Exact 15.9gr because of their accuracy. It pinned the bullseye with perfect vertical trajectory and off by 1/8" on the windage. When I put the pump back on it, the check valve tripped at about 1200psi which kinda surprised me how low it was. Until now I've been refilling from about 1.8k - 2.0k, just kinda guessing at when it needs it.

GarthThomas · « **Reply #30 on:** January 28, 2013, 05:56:00 PM »

That's where it would be nice to have a pressure gauge on the rifle, so you can pin point the beginning and end of the sweet spot. Otherwise all you can do is fill abit less and try again, repeat as many times as necessary until your sure. It looks like you will get a a nice shot string for about 30 shots. JMO

tobar832 · « **Reply #31 on:** January 28, 2013, 07:59:24 PM »

Jason,
That shot string that you posted looks OK to me. It's got that bathtub shape, plus a great shot count. I think mine AG is in the same ballpark. Hard to tell without a Chrony, but I bought one today. It should be easy to pick you sweat spot out of that string.
I tried starting strings at 2900psi, 2500psi, and 2000psi. and what I can't get is the starting out seems quiet then gets louder and louder. It's using more air I know but does it always have to build up to a faster FPS? It takes about 8-10 shots before it starts getting louder. I would figure that if you start at the lower fills say 2000psi it should jump right into faster FPS and have the louder sound. When you pick your sweet spot to start your strings are you always going to have to build up to your max FPS?
The smacking of these targets is the great part. I can't believe the groups I getting. Last night I picked up my B-26 and shot it. Springers are going to be hard to pick-up and enjoy till I wear myself out on these PCP's...lol. Been shooting .177 Crosman Premier 10.5 and been really happy with them.

nervoustrigger · « **Reply #32 on:** January 28, 2013, 08:12:59 PM »

Quote from: GarthThomas on January 28, 2013, 05:56:00 PM

That's where it would be nice to have a pressure gauge on the rifle, so you can pin point the beginning and end of the sweet spot.

Agreed, I'm very interested in installing a gauge but I'm assuming it must be major surgery because I couldn't dig up anything about it other than where someone asked the question. If you find out how, please share!

nervoustrigger · « **Reply #33 on:** January 28, 2013, 08:21:57 PM »

Quote from: tobar832 on January 28, 2013, 07:59:24 PM

I tried starting strings at 2900psi, 2500psi, and 2000psi. and what I can't get is the starting out seems quiet then gets louder and louder. It's using more air I know but does it always have to build up to a faster FPS? It takes about 8-10 shots before it starts getting louder.

Hmm, I'm surprised you were detecting a growing loudness down at 2000psi. There's a pressure at which it shoots at max velocity and if you know about what that is, you can pump to it and go from there. Problem is knowing where that is without a gauge on the rifle. What I intend to do is, the next time I'm out plinking, occasionally fire one off through the chrono. When it's in the vicinity of the max velocity of 900fps, I'll attach the pump and see at what pressure the check valve opens and then I'll know about where it needs to be.

GarthThomas · « **Reply #34 on:** January 28, 2013, 11:54:42 PM »

After reading this post I decided to see what my B50 would be like with original spring and transfer port. I decided to fill to 2600 hoping to nail the sweet spot on your graph. My hammer has been polished and lightly lubed as well as a bit of deburring and polishing in the tube.
So here goes, when it was done I was at 1800psi. Using CPHPs 14.3.
880 914 901 879
886 921 905
896 919 896
896 917 897
893 917 888
907 919 889
904 911 887
914 914 882
913 916 884
917 901 887
It's definitely louder and I don't like pumping to 2600 but it was fun.

nervoustrigger · « **Reply #35 on:** January 29, 2013, 01:00:45 PM »

Tobar, looks like you may be right about the peak power coming at around 2000psi. Last night, I hit what I consider the power band (>870fps) when the pressure had fallen to about 2200psi.

YoteMaster · « **Reply #36 on:** January 29, 2013, 07:57:06 PM »

nervoustrigger, Your profile pic is perfect!

nervoustrigger · « **Reply #37 on:** January 29, 2013, 08:14:29 PM »

Ah, thank you. Preparedness is key!

Been following your yote escapades. Really I'm jealous I don't have any around here. Good luck!

YoteMaster · « **Reply #38 on:** January 29, 2013, 08:24:38 PM »

I'll share plenty of pics, video and play by play.

I ordered a scope cam mount this morning so I can video the kill shot.

YM

YoteMaster · « **Reply #39 on:** January 29, 2013, 08:51:50 PM »

Just for reference, this is the PCP pressure gear I purchased...

http://www.gatewaytoairguns.org/GTA/index.php?topic=41625.0

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My first PCP

Author Topic: My first PCP (Read 11488 times))