Some Interesting Service Data.

Please check first as some of this work is no longer undertaken, due to lack of spares etc.

I mostly work only on Air Arms - Weihrauch HW100 these days.




AirArms S410 Carbine .22 Leak Issues and Quickfill Conversion
This air rifle came in with the usual service requirements and a very low power issue.
The customer complained about the early fill fitting not only being bulky and marking the moderator, but seeming to leak and this
was the second such fitting failing in 2 years. Normally I just fit another valve, or offer to convert to the latest Tee piece filtered

Air Arms fill system.
I can NOW offer a good alternative costing slightly less than the Tee piece unit whilst being FULLY servicable.
This is a quickfill valve system used by several manufacturers which is less bulky and easier to fill.
I can undertake this whilst the rifle is in for a service and would transform the filling procedures making it far easier.


Quickfill Adaptor


Theoben Rapid .22 FAC .
I designed and fitted a mini regulator to this rifle over 2 years ago. It was serviced and power tested after being used all last year.
NO air loss reported and after quite a time of no usage the power level and fps was the SAME no creeping or loss.
Last time I checked it with AA Fields 16gn it gave 902.93fps (29ftlbs). Then after approx a year the first shot gave 894.85fps then consistant at 902.93fps to 900.90fps. AMAZING.
This has a 20 inch barrel that I fitted and re-crowned, together with my own designed Mini Regulator/ Quickfill gauge unit.
The main issue most customers raise is either the rifle power curve is poo,r or they find it a pain to keep removing the bottle,

and not knowing the air pressure level.
My regulators or quickfill/gauge units solve all these issues.This works for NONE FAC as well.

Air Arms FTP900 Issues.
I do not see many of these as most of my work is on the Air arms EV2.This one came in from a serious circuit target shooter
For me to sort out a fillling issue only, but the request was also to give it an inspection as well. There was an attempt to lose weight

by removing certain parts and I understand this is quite common. The main issue I found was it had an erratic leaking regulator and

The gauge fill system was missing, replaced by the original early type fill system. I found out the regulator was none standard internally.
Air Arms were really helpful to me in establishing various factors.Their Production & Design Department really went out of their way to help.
I now have all the information I need to sort this out. Next stage is rebuilding the regulator and adding the corect filling/gauge body.

Theoben Rapid MK1 in both .22 and .25 calibre
Funny I have never had a .25 calibre in to date then 2 turn up in the same month.The usual issues were found and these

included bent firing valves and valve bodies, that needed some re-work. Also I converted all four to quickfill models and this makes

filling a doddle, as well as giving you the very important air pressure via the gauge.
I am in the process of designing my own regulator/quickfill unit which should work direct on the old MK1 Rapids without any need

to alter the porting.


Theoben Rapid MK1 .20 calibre
Another Rapid Mk1 in .20 calibre which had various issues including worn seals and leaking.
I found the power curve very poor and fitted a test regulator, which transformed it, although slightly low in power

which was to be expected with MK1 porting, so I could go this route although the rifle was fitted with a

poor design original Theoben gauge unit which located against the breech face. By tweaking the internals, I managed
to get a very good 11.50ftlbs power from 180 to 95 bar. This was a surprise, as normally I do not get anything unregulated.
The customer was pleased and he is now considering my quickfill /gauge regulator unit to finish it off.

Theoben MK1 Rapid leaking and very low power.
This was an unusual one and I immmediately checked all the internals to make sure all was standard.
The owner confessed to changing various parts to "custom ebay parts" which I changed back again.
A small part of the solution was changing the old type schrader valve assembly first then checking all the porting and flow.
After this the power curve was dire so I fitted my own designed Regulator and Quickfil/Gauge system.


Weihrauch HW100 .177 Service & Sort Out All The Wrong Settings & Incorrect Parts.
This one after hearing the owners brief history on the problems & work done by what looks like unqualified hands,
Would have been a rifle I would not normally entertain looking even at.
This time and bearing just after Christmas I thought the spirit would be to help on this occasion.
Yes as expected seals missing or fitted in incorrect places.
Also this rifle had a cylinder which was not the standard Weihrauch one and caused some after service issues.
I will ONLY work on HW100 air rifles that are totally standard & the issues found with this air rifle bears out why
I do this.

My policy to not work on PCP air rifles that have been tampered with seems to make sense here.

Theoben MFR .22 Service Pellet Removal & Added My Designed Gauge/Quickfill System.
Service & regulator check & reset on test rig. Also had to remove 12 pellets from the barrel.
Gave it a standard fully comprehensive service on both the rifle and the regulator.
The customer was a bit fed up with having to remove and replace the bottle and had a system of filling it

every month. This did not account for the bottle seal leak, which lowered the pressure to the point his

Gardener using the rifle fired it, not realising there was no power & jamming pellet after pellet in the barrel.
I set about designing and manufacturing my quickfill/ gauge system, which now means no more problems.


MFR Quickfill

RAW TM1000 Target Rifle
Service & regulator check & reset on test rig. Customer had an issue with accuracy as some pellets would seem to go anywhere.

I stripped and serviced it & found the carbon fibre shrould system adaptor was .010" (.25mm) out with the rifling, also crowning was not great.
The barrel its self was quite loose in the rifling over a fair part of its length and choked as standard at the end.
Totally stripped serviced and rebuilt it, then screwcut & re-crowned the barrel end, finally removing the carbon fibre shrould idea & fitting with a customers moderator. Power set & repeated at 775fps. Next stage is to field test this which the customer is in the process of doing.

Air Arms EV2 Mk1
Internals modified and put back to standard. Regulator serviced re -machined and rebuilt. Looks to have been modified and did not improve

it either.
Serviced and tested 775fps perfect JOB DONE.

Theoben Rapid FAC
Servicing required but found internals were similar to a sub 12ftlbs, just 2 large hammers springs fitted
And called an FAC!!!!!!!!. Shot count and power curve was virtually usless.

Totally rebuilt and all the internals reworked. Added new parts to improve power flow.
A quickfill unit would enable the customer to both fill and have an on board gauge with a regulator to give a constant accurate FPS.
I rarely see any so called FAC Theobens, that work in both power curve and shotcount WITHOUT A REGULATOR.

Air Arms S410 Carbine
the power level set incorrectly & wrong seals in gauge assembly.

Serviced and power reset and tested JOB DONE.

Air Arms S400
had a slight pinging sound in breech when firing now resolved and fully serviced.

Weihrauch HW100
regulator setting incorrect & found a loose inlet valve assy with PTFE tape.
Serviced and rebuilt now functioning as it should.

Air Arms S400
which had 11 pellets lodged in barrel & all the internal settings were not correct.

Serviced now working correctly.

Air Arms EV2 MK2 Abuse.

This one came in from a very valued customer, who already owned a MK5 and needed a back up rifle only. He is a very

Serious and compentent target shooter well known on the local club circuits.
POINT ONE: I found the venturi port damaged with the thread stripped and missing the venturi adjustment screw.
POINT TWO: The Hammer adjustment has seen someone using I would say a pistol drill to add holes VERY BADLY. system
And possibly forgot about the AT, resulting in the thread being loose and marked.
POINT THREE: An attempt had been made to fit a moderator using an adaptor which was eccentric to the barrel probably

causing pellet clipping and inaccuracy hence it was sold as being not reliable.
I feel this rifle has been discussed with me before by at least one of its previous owners.

I stripped and serviced rebuilt the rifle which now shoots well and the regulator is perfect.
I designed and manufactured an air stripper which works keeping the rifle less noisy than the conventional one and
Just waiting for feedback on this one once it has been field and target tested watch this space.
So if you have EV2 issues specffically REGULATOR PROBLEMS give me a shout.

Theoben Rapid Poor power curve .22

When I inspected this air rifle it soon showed a degree of tampering being carried out.There had been an attempt to increase the power level but this only produced a very poor unusable power curve.
In the end I stripped and took out all the non standard parts, then rebuilt it and tuned it slightly to improve
the power to 24FPS from 124fps.
Had I have fitted a regulator then it could be improved significantly.
At the moment the customer is going to use it then I could well be fitting both a regulator and a gauge/quickfill system.
I still would prefer to fit a regulator straight away!!!!!!


Theoben Rapid 17/.177 with a .22 barrel.

This customer wanted to purchase a Theoben Rapid & asked my advice, which I went into in depth on what to look out for and the pitfalls etc.
He ended up purchasing a Theoben Rapid .22 air rifle and then discovered the block was marked up 17/.177cal and called me to inspect it giving him a detailed report.
This one was in fact a .177 breech block .22 barrel rifle which I would say has had some porting and spring changes.
The valve was bent and various other factors, pointed to the rifle being over stressed.The decision was just to

service and rebuild and correct any problems found.
I soon found out the power curve was not good, & decided to fit a regulator. This meant also sending a fair amount
of time testing and playing with springs and preloads.
My tests below show the differences between regulated and non regulated and I would say getting it to perform without
the regulator would be nearly impossible due to the changes I found.
Test from 80 bar to 180 bar 213fps Variation so not constant or accurate.

Bar Graph

Regulator Fitted.

100 to 180 bar variation 7FPS so this gives a good shot count and accuracy throughout the range


I would say although some Theoben Rapids can run non regulated, most are better off with one.


Air Arms EV2 MK5 varying FPS issue.

In from a very serious target shooter, using around 10,000 pellets a year. Due to the amount of use it actually gets,
I service and test this piece of kit a lot sooner than normal.
My initial tests showed this to be mechanical rather than any regulator issues. While it was in I decided to try some very comprehensive testing & this was all directed at the regulator design and function.
There has been a fair amount of discussion within target shooters and the forums about this regulators efficiency, so I

decided to try 2 ideas.
1: Design new internals to fit within the existing regulator body.
2: Design a new complete regulator.
My new designs were fully tested and the conclusion is the regulator its self works very well and there is not much improvement

by changing the internals which only gave me a slightly higher FPS from cold on the first shot than the existing design but
the constant fps was very similar over a 25 off weighed pellet test so not worth doing.
The whole new regulator design which kept the gauge in the original place was again needing some tweaking but gave similar
results to the original.
BOTTOM LINE I am sticking with the original regulator.


Air Arms S410.22
Leaking and found the main body valve face damaged so the firing valve would not seal.
A general inspection showed a full service was also needed. I re-plotted the power curve, and this gave around an 18 FPS variation only over the complete fill range. Who needs a regulator.

HW100 .177
Customer complaint leaking. My initial inspection showed the cylinder to be the culprit.
Full service and regulator service and reset cured the problem and gave it a tad more power from 10.70ftlbs to 11.30ftlbs.
Happy Customer.



Air Arms S410 Classic .22
A Pest Control Working Rifle & customer complained of inaccuracy.
Stripped serviced power curve checked and power increased slightly.
Found several issues with loose parts,

worn seals & the system slightly gummy. Now back to where it should be and working for its living.


Weihrauch HW100 .177
Came in leaking and due to the excellent condition and age I considered just repairing the leak.

Not my normal practice as a full service is usually the only option.
I then carried out a compulsory power check and found this to be over the legal limits even with all the standard AT in place.
This meant some more work here unfortunately. I would alway suggest you keep an eye on this as Its not the first over powered
HW100 I have found.

Air Arms S410 F Classic .22

Customer complained of inaccuracy. Stripped serviced power curve checked and power increased

as was 9.50ftlbs only. range tested and made alterations to trigger and scope mounts. Now shoots accurately

and customer has scope settings from 30 to 50 yds as requested. The scope was really meant for a full bore rifle

hence one of the issues with accuracy.


6 Theoben Rapids and MFR's.
A mixture of air rifles came in the same month from a number of customers, including a pest controller.

These were both FAC and sub 12 units and required anything from a full service and regulator check/ reset

to just a power test and inspection.



Air Arms EV2 Mk1.
In for a complete service regulator re-set and check on my test rig and total rebuild.

This model had a pressure relief valve in the inlet body which had not been serviced at all so needed some work done

and I increased the pressure setting a tad as it was releasing air within the pressure range.

Now functioning as it should do with a constant FPS from the regulator.

HW100 .177 Is The Power Level That Important !!!!

I had a HW100 .177 in for service and repair with the complaint that is just makes a popping noise when you pull the trigger!!!!
I found out it must of had a major pellet jam judging by the amount of distortion I found on the internals.
Coupled with this was a total failure of the regulator which would function then fail on the same tests on my dedicated test rig.

Running extremely slow on the return rate was one feature.
After I serviced and rebuilt it with several new parts and some of my own modifications, I found the power level to only be around 10.00ftlbs!!! No more adjustments would improve this so I decided to take it off to the range for testing.
WELL SURPRISE SURPRISE it shot very accurately and seemed to hit very hard and fast.

The Target

Test target

I was not over concerned with zeroing the rifle at this stage but the group was fine.
This shows that 10.00ftlbs is still ok out to 30yds at least and power is not everything.
I did on the clients instruction raise this rifle to 11.30ftlbs to be fair.
We are talking 733 FPS to 770FPS here with a lot of off the shelf un-regulated rifles doing around 25 to 30FPS variation though the full to empty fill pressure.
HOPE THIS HELPS & I Have No Problems Using rifles which give this power level and would shoot to 40yds on targets.

Theoben Mk1 Rapid .177 Regulator Installed.

The rifle came in after being stored for several years. I inspected it and found several points that needed changing
to bring it back to its former glory.
This was a non regulated version & all my expertise to get a decent shotcount with a constant FPS did not work.
I alway try this first before resulting to a regulator, but to be honest a regulator is the only way to go.
I fitted one of my own manufactured Regulators then set about fine tuning all the internals to get both a constant
power level FPS and a higher shotcount, whilst the rifle giving a minimum stress and load on the internals.
So many I see have been vastly over sprung & are very hard to cock versions with massive internal parts strain
which we all know will eventually cause damage.
Job Done!!!! Another Theoben Restored to Its Former Glory.

Air Arms RN10 Pro Target Regulator Service & Revamp.

This came in for a service and I soon found out the regulator was in poor shape.My initial inspection revealed it needing a bit of work doing as well as a full service. I understand that these air rifles are not every service engineers cup of tea, but I found it a joy to work
on & an exceptionally accurate piece of kit which I found as good to me shooting it as an Air Arms EV.2.
Serviced and returned another happy customer.

I Look Forward To Hearing From You.