mubhaur said:

I understand that BC changes with many factors out of which fps is the most important as mentioned above.

Twist rate is also a factor. I understand that when a projectile is shot at higher fps from a barrel of a certain twist rate, it also achieves more rpm while leaving the muzzle.

RPM and fps are two important factors which are inter dependent if same twist rate of barrel is used.

Over the distance RPM do not drop as much as fps drops. This phenomenon is also important in BC as I feel.

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woogie_man said:

Here are the results of 2 hours of shooting at the range today. The shooting tubes are indoors, a local underground range that is 2 blocks from my work. It was a moist 68* and rainy outside, so that made the range a bit chilly but mostly dry. I started shooting at 25 yards to make sure things were working ok since I added the plenum extension, and having had to disassemble the rifle and bend the inner probe back. After I made sure things were shooting ok I started with the testing.

Each group is 5 shots, unless the chronograph didn't pick up 5 shots and I shot more to get a consistent numbers. Where you are seeing the +1 turn and then just +1 etc this is the hammer spring adjuster on the rear. I marked the adjuster just like I showed when I was playing with the AAA HPS30. This helps in keeping things consistent and easy to index. I REALLY wish companies would add hash marks around the outside of the adjuster to help in tuning. Would be a great little addition that wouldn't add to much to the overall cost of the rifle.

I was doing rough adjustments on the rifle to see what I was able to accomplish. The 25 grain range of slugs shot great and I could feel a difference in the shot cycle when shooting. There didn't seem to be as much stress on the rifle and the valving sounded smoother while cycling. I did shoot some 30 and 34 grain Javelin V2 slugs just to see what speeds I can get. I was able to get close to 900 fps with the 34 grain slugs and there was still more hammer tension I could add. Now I didn't adjust the regulator as I didn't have any of my equipment to adjust and don't want to adjust just yet. Saying that the felt recoil was quite a bit more when going with the 34 grain slugs. You could really feel these slugs when shooting and I was honestly shocked. I have no doubt that the gun will shoot them but the effect it will have on the shot count is unknown at this point.

Speaking of shot count........ The rifle fills to a max of 250 bar. I was able to shoot 2 targets, so 10 shots with only 10 bar of pressure lost. I am looking at getting a digital gauge for the rifle so I can see exactly what the efficiency of the rifle is. But being as my main focus is to use this rifle for NRL22 matches, having 12 full powered shots I am ok with the shot count at this point.

Over all I am looking at the Corbin .218 X Hollow Point, this is one of their newer products, and they were shooting shockingly good. At the end of the session I was shooting from 25, 50, 75, and 100 yards at a new bull for each distance. And you can see the dispersion but it was consistent and I can't wait to get the gun out and hopefully shooting a few gophers and bunnies with it. My shooting buddy and I have been talking with Corbin and will be working on getting videos and pictures while using them The other slugs I am going to play more with are the H&N Slug HP that are 25 grains as well as the JSB KnockOut in the 25.39 grains, both in the .217 size. This is what kind of confused me and frustrated me..... is the rifle was shooting both of these sizes very well!

I did start the 50 yard page with just a naked barrel. There was the adapter for the DonnyFL Ryu quick release adapter on the end, but no muzzle break or anything like that. I wanted to see what the rifle would do with a bare barrel and then add a moderator or muzzle break to see, if any, difference these will have on the groups. I do have a DonnyFL Ryu and Yokozuna, and Impulse Air 1350, a muzzle break that I purchased from South Africa, and a tunable muzzle break from Eagle Vision. I will get a group picture of them all so we can all see what is going on.

Over all I left the range with one heck of a headache, and ready to get home and shower. Being as I went from my job right to the range I was gross and slimy from a rough day at work. One thing I did notice is that the H&N slugs I had previously had, and finished off at the range, had a weird waxy lubricant on them. But the tin I opened up during this shooting session the slugs looked clean and didn't have that waxy looking appearance to them? I am also debating on trying some of the JSB KnockOuts in the V2. Not sure there will be any difference between the flat walled V1 and the flared base of the V2.

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triggerGenetics said:

def nice write up, thinking on getting on… either the 11 or 12. where did u get yours if u dont mind sharing…?

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primaz said:

That will work. Take a closer look the moderators shown above when they are not attached; you will see that where they screw in to the barrel that it the same and that because the stock GK1 has a longer barrel than the shorty, Torquemaster provides these different size spacers to fill that gap. Thus on a shorty you might not need much of a spacer if the end of the barrel and the end of the air chamber are the same? Only if the chamber is longer than the barrel would the moderator need to be modified and if that is the case, send an IM to IMADMAN whom designed it as he might be able to just tweak the CAD design so that Torquemaster has a different file to 3d print a version for you.

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Hold_Over said:

Came across an Umarex rifle I couldn't help but click on out of confusion based curiousity. The tactical styled, collapsible stock, h/k mp7 replica in a low velocity break barrel single shot format. Under 500 fps in .177 it has little practical use or entertainment value.
https://www.umarexusa.com/2252312
What kind of strange/borderline useless stuff have you guys come across searching the web?

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