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TX200 Accuracy Restored

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Fred J:
Recently, I replaced my OEM spring on my TX200 after 30,000 shots. I had TbT spring guides on it, and it really shot well with this combination, but the power had decreased from 15 fpe to 13 fpe. So I ordered a new spring from PA and new guides from TbT. At first my TX200 had an extremely harsh shot cycle after replacing the spring. Unfortunately, after shooting the TX for about 1,000 shots, the shot cycle was still extremely harsh. The rifle was real hard to cock, and when I shot the rifle, the sight picture jerked to the right. So I put the rifle in the gun cabinet, and just shot my AA S500 at this years field target competitions.

Now that Winter has arrive in Wisconsin (11 F right now), my airgun club has moved indoors. We have what is call Indoor Field Target Practice (IFP), where we shoot 25 bulls , with a maximum score of 50 points. For this IFP competition, I shoot my TX200. So out came the TX, and I struggled to get 25 points last week.

This week I was down in my new basement (I just moved) getting my gun smithing bench set up, and I thought: A few years back I tried out two Vortek tune kits: A 12 fpe kit and a SHO kit. I looked through my moving boxes, and I found the ziplock bag with the two Vortek tune kits inside. The springs were all lubed up with clear tar, so all I had to do was open up my TX and reinstall them. The first kit I installed was the 12 fpe kit, which had about 5,000 shots on it, and found that the power was down to 9.5 fpe. The shot cycle was excellent, with little recoil and no vibration. However, 9.5 fpe was just too slow for me, and the AA 7.9 pellets did not group that well.

So out came the 12 fpe kit and in went the SHO kit. Wow!!! The TX now had 12.35 fpe, and the shot cycle was excellent. It's shooting AA Exact Expresses (7.9 gr) at about 840 fps.

I took my SHO tuned TX200 to the airgun club yesterday, and after zeroing my scope, shot a 40 point IFP, after warming up the rifle with just 10 shots (see picture below). A 40 point IFP is considered exceptional IFP score for a spring piston rifle at our airgun club. During the shot cycle, there is no significant movement in the sight picture, and the rifle is easy to cock (about 22 pounds). The TX with the old SHO Vortek kit is more accurate than my TX was with my old OEM spring and TbT guides, and the shot cycle is much milder. So I am going to leave things alone for now, and hope that the old SHO spring does not break.

I wish I took pictures during my retuning effort. One thing I notice was the SHO spring was exacting the same length as the 12 fpe spring, even though the SHO spring has two more coils that the 12 fpe spring. The amount of preload was just 1/2 inch for both springs. So the lesson I learned is to never throw away old springs and spring guides, unless, of course, they are broken.

nced:

--- Quote from: Fred J on November 20, 2022, 09:33:56 AM ---Recently, I replaced my OEM spring on my TX200 after 30,000 shots. I had TbT spring guides on it, and it really shot well with this combination, but the power had decreased from 15 fpe to 13 fpe. So I ordered a new spring from PA and new guides from TbT. At first my TX200 had an extremely harsh shot cycle after replacing the spring. Unfortunately, after shooting the TX for about 1,000 shots, the shot cycle was still extremely harsh. The rifle was real hard to cock, and when I shot the rifle, the sight picture jerked to the right. So I put the rifle in the gun cabinet, and just shot my AA S500 at this years field target competitions.

Now that Winter has arrive in Wisconsin (11 F right now), my airgun club has moved indoors. We have what is call Indoor Field Target Practice (IFP), where we shoot 25 bulls , with a maximum score of 50 points. For this IFP competition, I shoot my TX200. So out came the TX, and I struggled to get 25 points last week.

This week I was down in my new basement (I just moved) getting my gun smithing bench set up, and I thought: A few years back I tried out two Vortek tune kits: A 12 fpe kit and a SHO kit. I looked through my moving boxes, and I found the ziplock bag with the two Vortek tune kits inside. The springs were all lubed up with clear tar, so all I had to do was open up my TX and reinstall them. The first kit I installed was the 12 fpe kit, which had about 5,000 shots on it, and found that the power was down to 9.5 fpe. The shot cycle was excellent, with little recoil and no vibration. However, 9.5 fpe was just too slow for me, and the AA 7.9 pellets did not group that well.

So out came the 12 fpe kit and in went the SHO kit. Wow!!! The TX now had 12.35 fpe, and the shot cycle was excellent. It's shooting AA Exact Expresses (7.9 gr) at about 840 fps.

I took my SHO tuned TX200 to the airgun club yesterday, and after zeroing my scope, shot a 40 point IFP, after warming up the rifle with just 10 shots (see picture below). A 40 point IFP is considered exceptional IFP score for a spring piston rifle at our airgun club. During the shot cycle, there is no significant movement in the sight picture, and the rifle is easy to cock (about 22 pounds). The TX with the old SHO Vortek kit is more accurate than my TX was with my old OEM spring and TbT guides, and the shot cycle is much milder. So I am going to leave things alone for now, and hope that the old SHO spring does not break.

I wish I took pictures during my retuning effort. One thing I notice was the SHO spring was exacting the same length as the 12 fpe spring, even though the SHO spring has two more coils that the 12 fpe spring. The amount of preload was just 1/2 inch for both springs. So the lesson I learned is to never throw away old springs and spring guides, unless, of course, they are broken.

--- End quote ---

Good write up!

A few years ago I tried an "other than ARH" spring kit and bare spring and was disappointed by the rather rapid sagging of the coils giving noticeable velocity decrease by 2500 shots and significant velocity degrade by 4500 shots. The first full kit I tried in my .177 R9 with the thick steel top hat gave a "too hot for me" 7.9 grain velocity of 960fps so I cut a thinner replacement top hat which dropped the velocity to an acceptable 910fps. After 2500 shots the velocity had dropped to 880ish fps so I replaced the home turned top hat with the original thick top hat and the velocity was again about 910fps with CPLs. The velocity kept dropping to the point that the velocity with CPLs was 880fps at 4500 shots (80fps less than new) in only 4ish months since I was shooting about 1000 shots per month at that time. The spring kit that sagged had a strange configuration where the end coils were open instead of closed, however a couple years later I noticed that the vendor was closing the spring ends so I ordered a new bare spring, fitted "home turned" spring guide and top hat, installed in the R9 and noticed that the R9 velocity dropped from 910fps new to 880fps in less than 2000 shots. 880fps with a 7.9 grain pellet is more than satisfactory however the rapid degrade prompted me to pull the spring kit and install a new home rolled spring kit based on the ARH E3650 bare spring that I've used for a long time.

As a side note, I personally prefer a 7.9-8.4 grain .177 velocity of 850-860ish fps for my break barrel HW springers and find it interesting that you found that 12.5-13 fpe works well for you.       

DanD:
That's great that you found a good setup. I'd think your SHO kit is sacked out or missing spacing to be shooting so slow.  But sacked out SHO kits can shoot pretty nice. I had one in a .177 HW50 that started out at 12+ fpe and after a few years was around 10 fpe and a little friendlier.
I keep all my old guides and springs and mix and match them to find combinations that work well in various guns. 

Jason_Garvin:
Well you pertinear got your money’s worth on that 30k shot spring.  If that TX was shooting harsh something was off, every one I have owned and tinked on shoot real smooth.  Even with a polish and lube, OEM parts will shoot nice.

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