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Tuning Is the HW97 Vortek pg4 HO kit a little for spicy for .177?
- Thread starter luckybuckeye
- Start date
I like the 12ftlb kits in my 97K. I actually took a coil off and am running mine at 10.5ftlbs. Its very easy to cock and accuracy is spot on out to the 60yds I use it at. Windy days make it interesting though. I usually switch to my .22 97K with the HO kit installed. 17fpe and handles wind much better.
If you're dead set on an HO kit in the .177 97K you'll probably either want to use JSB 10.3 or trim the spring some.
If you're dead set on an HO kit in the .177 97K you'll probably either want to use JSB 10.3 or trim the spring some.
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Thanks for the reply. I currently have an older 12 fpe Vortek kit installed. I did put in one power washer because it was only putting out 11 fpe. With the washer installed I have to get aggressive with the cocking arm otherwise the safety won’t engage. Sounds like I should take out the washer and enjoy the gun. I really do like the decreased cocking effort. I’ll save the HO kit for my next gun.
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Will depend greatly on the pellet you use and even going up a mid-weight .177 pellet you should be well below 1100 fps. Also, the spring is an open coil design so cutting one or more coil(s) is easy to do to get to a lower velocity (if you want). If I recall my HW97 with Vortek kit and 7.9gr pellets produced about 980 fps and was very accurate to FT max distance 55 yards.
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Take the guide out and just trim 1/16"-1/8" off the top of it. That'll allow the gun to fully cock rearward and engage the safety. The quick and easy way to do it (if better tools aren't available) is to hold the guide like a pencil and run it back and fourth aggressively across some coarse sand paper, measuring as you go. When you're at the diseired length clean it back up with some finer 1000 grit paper.
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I'm re-looking at this and that has to be a typo. Theres no way you're getting over 21ftlbs out of a .177 97K (or even a .22 for that matter) which is what a 7.9gr at 1100fps would be. He actually claimed 18fpe right about that which still seems high but it would be closer to 1000fps with a 7.9gr.
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I can give you some numbers in a HW77K with the PG4 HO and his vac seal
Using the 10.34 jsb averaged 813 fps @ 15.12 fpe
That was with no washers, and the kit comes with 2, so it would be a considerable jump adding washers
I can tell you it was Not pleasant to shoot, the shot cycle was a small improvement over stock and the twang was a tad less, but the recoil was substantial.
These were my personal results, of course others may vary.....
Using the 10.34 jsb averaged 813 fps @ 15.12 fpe
That was with no washers, and the kit comes with 2, so it would be a considerable jump adding washers
I can tell you it was Not pleasant to shoot, the shot cycle was a small improvement over stock and the twang was a tad less, but the recoil was substantial.
These were my personal results, of course others may vary.....
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I also found the HO kit to be over-powered in my hw97k. Went to an ARH 12fpe spring and the shot cycle is a lot more pleasant with great accuracy.
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My 177 97 with a PG3 HO kit was making 15 fpe. IIRC correctly i cut a coil and it shoots FTTs 8.64 at 860 for about 14 fpe. JSB 8.44s make a about 14.5 fpe. The gun will shoot dimes sized groups at 50 yards.
More recently I put an uncut HO PG4 kit in a 22 caliber Hw97 it made about 16 fpe with 14.66 FTTs.
The most power I've heard of from a Vortek kitted 97 with lead pellets was about 17.4 fpe. I suspect that gun was dieseling badly.
The 97 and 95 have the same bore and stroke (within 1mm). The kits use the same spring. 31.5 coil 0.785" I've done several of these. Usually start off a little over 15 fpe in 177 and a little over 16 fpe in 22. They settle down a tick after a few thousand shots.
More recently I put an uncut HO PG4 kit in a 22 caliber Hw97 it made about 16 fpe with 14.66 FTTs.
The most power I've heard of from a Vortek kitted 97 with lead pellets was about 17.4 fpe. I suspect that gun was dieseling badly.
The 97 and 95 have the same bore and stroke (within 1mm). The kits use the same spring. 31.5 coil 0.785" I've done several of these. Usually start off a little over 15 fpe in 177 and a little over 16 fpe in 22. They settle down a tick after a few thousand shots.
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I love the PG4 HO kits. I always trim one coil off and they shoot fantastic at about 15 fpe
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My .177 HW97K was about 15 fpe with a PG4 HO kit installed originally...now it's settled in to a little over 14 fpe. JSB 10.34=785 fps and H&N FTT 8.64=860 fps...If I were to do it over again I think I would go 12-13 fpe in .177 as I feel the smaller caliber doesn't efficiently transfer spring energy into projectile energy above about 12 fpe...
In my mind the .20 at about 14 fpe in the HW97K would be springer perfection...much better downrange energy transfer than the .177...
In my mind the .20 at about 14 fpe in the HW97K would be springer perfection...much better downrange energy transfer than the .177...
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I will say that the shot cycle isn't rough or unpleasant by any means. It just feels that it's not efficiently transferring energy like I think it should...
One way I know this is that a 8 grain pellet yields a significant more fpe vs a 10 grain pellet...
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You'll find it still loses efficiency with heavier pellets if you lower the spring pressure. Most springers are less efficient with most heavier pellets. It's pretty much the nature of the beast.
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The Vortek kit in my 95 produced the same power a the factory spring. Too spicy for me. I clipped almost 3 coils which toned it down nicely. 177 FTT @870 or so. Shoots nice.
I also at times run the 12fpe kit, which makes over 13 in my gun. 820 FPS if I remember correctly. Really smooth shot cycle.
I also at times run the 12fpe kit, which makes over 13 in my gun. 820 FPS if I remember correctly. Really smooth shot cycle.
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Not offhand. But its pretty common knowledge across many air gun forums. There's a British forum I occasionally go to. There they take this efficiency stuff to levels that are way over my head.
I do know from chronographing thousands of rounds through a couple dozen different Weihrauchs in three calibers that all of them were less efficient with just about every heavy for caliber pellet. Often drastically less efficient.
Those results match the explanations on the UK forums by much smarter people than I. I think it has a something to do with the limited amount of available air to a springer and the short time it stays peaked.
I certainly don't know it all but given the results of my testing and quality of the corroborating information, I just accept it as normal. You may not want to and that's fine.
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If by less efficient you mean lower FPE from the same gun under the same conditions, that has certainly been my experience. AA10.3s generally shoot 0.2-0.7fpe less than AA8.4s depending on the gun I’m using, all else equal. Never seen the opposite. In some cases, the 10.3s are the most accurate pellet for a given gun so I shoot those and don’t sweat the slight power loss.
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