Very Unusual CFX, CPL & Prochrono results

Very Unusual CFX, CPL & Prochrono results

Joined: February 5th, 2003, 4:48 am

March 28th, 2007, 2:24 pm #1

I’ve had a B-19 for 5 years that I home tuned with tar, moly,and new Apex seal when I got it, but I’ve had a love/hate relationship with it (mostly hate) mainly cause I could never get it to shoot as accurately as I wanted. I recently added a GTX trigger which has helped but I still thought it should do better. I wanted to tinker myself and I was itching for a new gun so I bought a Gamo CFX and a Prochrono Digital. I figured between the CFX, which is known to be pretty accurate and easy to shoot, and the chrono I’ld be able to get a good read on the B-19’s mechanicals, a comparison on shooting technique of two different springers, and basically determine what potential to expect from the B-19. Of course, I also wanted to start tinkering with the CFX.

Part 1 - I wanted to start out by getting a baseline on both guns with the Prochrono and various pellets. This is where the fun begins. It was a less than ideal day, very bright sun and windy. Here’s the sequence from that day:

- B19 w/CPL avg 630 fps +/-8 I thought this was very low, must be a spring problem.
- I wanted to quickly check the chrono so I grabbed my Marksman 2004 w/CPL but I got 354 fps. I thought this was very low, but an extremely consistent string. I next tried the 2004 with a Gamo Match and got 413fps which is about what I’ld expect (again very consistent string).
- Then I tried the Gamo Match in the B-19 and got about 775fps (very consistent string,..I’ll stop saying this because all my chrono strings were consistent). I thought this was still low for the B-19, and 150 fps is big difference for pellets that are suppose to be only 0.4 gr difference.
- Next was the CFX:
- CPL 727 fps Surprisingly low
- RWS Suprdome 866 fps Seemed about right.
- FTS 741 fps Was expecting higher, this is >2ft/lbs below the RWS
- CPL 726 fps Still very low but matched the first CPL string

I called it a day but didn’t know what to conclude. The conditions were lousy, the CPL results were crazy, but the strings were extremely consistent, no read errors on the Prochrono, and the CFX/CPL result was repeated identically.

Part 2 – Last night I rigged up some lights indoors just to see if I could get the Prochrono to work inside and do more testing. To cut to the chase, it worked fine and I got nearly identical results.

Part 3 – I brought a few pellets of each type with me to work today to weigh them on our professionally calibrated analytical scales. Guess what,…the CPL’s I have are really CPH’s. They averaged 10.6 gr. All other pellets seemed ok but the Gamo Matchs avg 7.8gr vs a nominal spec of 7.5gr.

My comments/questions/conclusions:
1. Watchout for CPL’s that are CPH’s!!!
2. The Prochrono seems great, easy to use, not sensitive, no read errors, and I’m concluding that it is calibrated precisely based on the Marksman 2004 Gamo Match results, and overall repeatability/consistency.
3. My B-19 needs some work. It averaged between 9.4-10.6 ft/lbs. I have a new JM spring and seal I will try.
4. I’m not sure what to think about the CFX. The RWS Superdome results seem OK. A little low, but maybe that’s normal for brand new gun. However, the variation in muzzle energy between the RWS (13.5 ft/lbs) vs FTS (11.1 ft/lbs) & CPH (12.4 ft/lbs) is bigger than I would expect. Comments?

Sorry for such a long post, but I would appreciate any comments particularly on the CFX.

Regards,

Ron
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Joined: October 18th, 2005, 11:38 am

March 28th, 2007, 3:15 pm #2

could just be an accident in production.
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Joined: February 5th, 2003, 4:48 am

March 28th, 2007, 3:21 pm #3

I didn't want to appear to bash the vendor because I haven't contacted them yet and I believe in actuality it must be a manufacturer error. I bought the 1250 count box from Pyramid Air. They are clearly labeled (I assume from the Crosman factory) as CPL's.

Regards,

Ron
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Joined: May 2nd, 2006, 4:27 am

March 28th, 2007, 5:40 pm #4

<P>That's funny I just got 4 boxes of cpl's from them and  all 4 boxes are the correct weight. The back of the box gives you the die number and the date.</P>
<P>The last batch from them a few months ago were die #7 with a Nov. 06 date and the latest batch are die #1 and a Jan 07 date.</P>
<P>Must be a packing error form the factory.</P>
<P>The pellet diameter also makes a big differene on crony results along with the pellet weight the main thing is consistancy between shots.</P>

http://home.comcast.net/~peterdragin/index.html/
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Joined: February 5th, 2003, 4:48 am

March 28th, 2007, 6:09 pm #5

Rich, I was hoping you'ld jump in here. I don't have the box in front of me, but I know it has Die #7 stamped on it and I believe it was Nov 06.

Can you comment on the muzzle energy data from my original post. It looks low to me and a big variation between RWS Superdomes(13.5) and FTS(11.1) and CPH(12.4), but I checked a few other posts on the forum and I see some others were getting similar numbers for these pellets? What's your experience for a stock gun with ~100 shots through it. I want the CFX for target not hunting so I guess the consistency is more important than absolute power.

Regards,

Ron
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Joined: May 2nd, 2006, 4:27 am

March 28th, 2007, 7:40 pm #6

<P>My .177 CFX is shooting 7.9 gr &nbsp;CPL"s in the 860's and is very accurate, it has been tuned and has the old Tarantula spring in it but before it was tuned it was a little faster. The 10.5 CPH's are a nice pellet but the gamo dosen't have the power to push them very fast and they are hard on the spring.</P>
<P>The tune is what gives the close pellet fts spread, I don't really worry much if the speed is up in the mid to high 800's, I want the accuracy not the pellet speed. My CFX with the .20 walther barrel is shooting 11.4 FTS's at 740 fps but it deadly accurate out to 50 yards, like nickel size groups at 50 yds.</P>

http://home.comcast.net/~peterdragin/index.html/
Last edited by peterdragin on March 28th, 2007, 7:42 pm, edited 1 time in total.
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Joined: February 5th, 2003, 4:48 am

March 28th, 2007, 9:01 pm #7

I'll probably be contacting you soon for a tune kit for the CFX, but first I need to work on the B-19 and use the parts I've already bought.

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Joined: October 21st, 2001, 3:36 am

March 28th, 2007, 11:00 pm #8

I’ve had a B-19 for 5 years that I home tuned with tar, moly,and new Apex seal when I got it, but I’ve had a love/hate relationship with it (mostly hate) mainly cause I could never get it to shoot as accurately as I wanted. I recently added a GTX trigger which has helped but I still thought it should do better. I wanted to tinker myself and I was itching for a new gun so I bought a Gamo CFX and a Prochrono Digital. I figured between the CFX, which is known to be pretty accurate and easy to shoot, and the chrono I’ld be able to get a good read on the B-19’s mechanicals, a comparison on shooting technique of two different springers, and basically determine what potential to expect from the B-19. Of course, I also wanted to start tinkering with the CFX.

Part 1 - I wanted to start out by getting a baseline on both guns with the Prochrono and various pellets. This is where the fun begins. It was a less than ideal day, very bright sun and windy. Here’s the sequence from that day:

- B19 w/CPL avg 630 fps +/-8 I thought this was very low, must be a spring problem.
- I wanted to quickly check the chrono so I grabbed my Marksman 2004 w/CPL but I got 354 fps. I thought this was very low, but an extremely consistent string. I next tried the 2004 with a Gamo Match and got 413fps which is about what I’ld expect (again very consistent string).
- Then I tried the Gamo Match in the B-19 and got about 775fps (very consistent string,..I’ll stop saying this because all my chrono strings were consistent). I thought this was still low for the B-19, and 150 fps is big difference for pellets that are suppose to be only 0.4 gr difference.
- Next was the CFX:
- CPL 727 fps Surprisingly low
- RWS Suprdome 866 fps Seemed about right.
- FTS 741 fps Was expecting higher, this is >2ft/lbs below the RWS
- CPL 726 fps Still very low but matched the first CPL string

I called it a day but didn’t know what to conclude. The conditions were lousy, the CPL results were crazy, but the strings were extremely consistent, no read errors on the Prochrono, and the CFX/CPL result was repeated identically.

Part 2 – Last night I rigged up some lights indoors just to see if I could get the Prochrono to work inside and do more testing. To cut to the chase, it worked fine and I got nearly identical results.

Part 3 – I brought a few pellets of each type with me to work today to weigh them on our professionally calibrated analytical scales. Guess what,…the CPL’s I have are really CPH’s. They averaged 10.6 gr. All other pellets seemed ok but the Gamo Matchs avg 7.8gr vs a nominal spec of 7.5gr.

My comments/questions/conclusions:
1. Watchout for CPL’s that are CPH’s!!!
2. The Prochrono seems great, easy to use, not sensitive, no read errors, and I’m concluding that it is calibrated precisely based on the Marksman 2004 Gamo Match results, and overall repeatability/consistency.
3. My B-19 needs some work. It averaged between 9.4-10.6 ft/lbs. I have a new JM spring and seal I will try.
4. I’m not sure what to think about the CFX. The RWS Superdome results seem OK. A little low, but maybe that’s normal for brand new gun. However, the variation in muzzle energy between the RWS (13.5 ft/lbs) vs FTS (11.1 ft/lbs) & CPH (12.4 ft/lbs) is bigger than I would expect. Comments?

Sorry for such a long post, but I would appreciate any comments particularly on the CFX.

Regards,

Ron
http://www.network54.com/Forum/479035/m ... Here+ya+go...

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Joined: February 5th, 2003, 4:48 am

March 29th, 2007, 11:40 am #9

Lon, Thanks for the info. It looks like your gun was significantly higher ME (13-16 FPE) than mine (11-13 fpe), but yours shows the same variability among pellets. It looks like your was dieseling quite a bit. Do you have any data after the gun settled down or was tuned?

Regards,

Ron
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Joined: October 21st, 2001, 3:36 am

March 29th, 2007, 10:58 pm #10

I was trying a lot of different spring/tophat weight combinations. I settled on a "soft tune" using the factory spring with a 15 gram tophat. I was getting about 800-815 fps but a VERY smooth and gentle shooting cycle.

I highly reccomend disassembling these guns and a least re-lubing. It is best to look them over internally and use proper lubes, you never know what could be causing low velocities until you eliminate certain internal possibilities. Check the breech seal with the tissue test and make sure you have proper weight tight fitting pellet too.

Anybody is welcome to any test data I have, just understand that it won't be comparable to a stock gun.

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