USFT unregulated shot string

I had a chance to run a bunch of shots over the chrono today with my USFT. The goal was to make sure I'm still getting a fairly narrow extreme spread for the fill and refill pressures I've been using. With that goal in mind, I filled a little higher than I normally do, and kept shooting to a lower psi than normal. Keep in mind that this is an unregulated gun, using very low pressure (low pressure compared to about 99% of other PCPs out there)

For the first 10 or 15 shots I was kinda hit or miss on recording the tenth. 

JSB 10.34





I typically fill to 1450 and refill at 1250. Per these numbers, that would give me an es of 17.3 for 40 shots (902 up to 912.1 and back down to 894.8). 

It looks like I could fill to 1500 and refill at 1200 and get an es of 34.9 for 60 shots (887 up to 912.1 and back down to 877.2), at least when practicing.

However I slice it, pretty cool for an unregulated PCP using such low pressures. The trend with most guns these days seems to be the other direction, regulated and high pressure. 
 
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Very nice. I'm attempting the same thing with my Scorpion SE at around 11.5 ft-lbs for HFT. The gauge on the rifle isn't very accurate so I ordered a tee fitting and gauge from Best Fitings UK so I can nail down fill pressure more accurately. My Shoebox booster compressor has no gauge at all. Is USFT a kind of air rifle? Sorry, I'm a rookie and don't know what that is.
 
It'll do more fpe, this just happens to be field target legal. I have a .22 barrel and had it doing about 28fpe at one point. All it took was some adjusting of the hammer spring and opening of the transfer port. 

Mine is technically a Hunter also, I just have the USFT accessories like the knee riser and the thigh support. In fact, I asked Tim to make my knee riser with a rectangular base instead of the round, cupped one he typically uses. 

You'll love your Hunter, easily my best airgun purchase. Some guns lose their charm after owning and shooting them for awhile, my MAC1 Hunter has not. 
 
Hi C,

I kinda did the same test many years ago and found out the same thing.

USFT, unregulated here as well. Mine is set slightly higher. When chrono'ed at our state match the velocity was 911 fps for the 10.3's but the actual come ups in the ballistic program call for 925 fps.

For whatever reason my fill seems to work best from 1550 psi to 1350 psi. I've always found it an interesting thing that when it's warming I don't need a refill for a 40 shot course but if the temps cool down during the match I have to fill it near the end of the match to stay above 1350 psi. I could probably squeeze it through when that happens but I don't like to take the chance anymore.

But just plinking around it seems like forever before it starts hitting low enough to miss a 50 yard 1.5 incher. 

Love those USFT's!






 
Just shot this group with the same gun. #15 shots at 55 yards, sitting on a bum bag. Cold and shivering and caffeinated. Less than ideal conditions and had to hold off for wind quite a bit. Misreads on the wind got me on a few. Not an atypical group for this gun- I'm the accuracy limiting factor for sure. 

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Also just pulled this off, matching my personal high score for this game.

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Thanks John. 

Don't know how much it weighs, but it's heavy. And while that weight really helps make an accurate gun for the normal position shots, it makes offhand shots a challenge.

I'd guess it's 15 pounds all set-up, but that's just a guess as I've never weighed it. 

It's got a Falcon x50 scope mounted. If I remember right, that's 29 ounces (just a few ounces lighter than the Sightron siii 10-50 that's so popular in field target-i think those ounces are the lack of illuminated reticle in my x50). The scope came with a thick walled (HEAVY) sunshade that could double as a ⛵ ⚓. I don't use the sunshade for the overall weight and because it feels like it tipped the balance of the rifle too far forward. 

I also figured out my offhand shots are much more accurate if I take off the knee riser for them. Knee riser itself is pretty heavy. 

Finally, the gun came from Tim with a screw-in little piece of aluminum, about ✏️ diameter and maybe 5 inches long. It screws into the buttplate and goes under the armpit-a butthook of sorts. The only time I use it is for offhand shots. It allows a lot of the weight of the rifle to be taken up by leverage, under the armpit, and the fulcrum point being your forward hand under the gun. 

With all that, and a little bit of practice, I don't do too bad with the forced position shots. Just like anything though, practice makes perfect.