GTS break barrel

[cooper_dan]

Quick update from today. Just done my first dry fire test

From what I hear, recoiless springers like the Park or Whiscombe can suffer a lot of damage if dry fired even once (strangely I can't find anyone to test this for me....). However mistakes do happen, so I've designed in some 'dry fire protection'.
This evening I've chrono'd the rifle. Then done 5 dry fires and chrono'd again. The result is an average muzzle speed drop of 6 fps (using jsb exact .177). The gears and gear racks appear unaffected.

So overall a very good result. Now I'll do another 1000 or so normal shots, then another round of dry fires.

[Geezer]

Quick update from today. Just done my first dry fire test

From what I hear, recoiless springers like the Park or Whiscombe can suffer a lot of damage if dry fired even once (strangely I can't find anyone to test this for me....). However mistakes do happen, so I've designed in some 'dry fire protection'.
This evening I've chrono'd the rifle. Then done 5 dry fires and chrono'd again. The result is an average muzzle speed drop of 6 fps (using jsb exact .177). The gears and gear racks appear unaffected.

So overall a very good result. Now I'll do another 1000 or so normal shots, then another round of dry fires.

In general, I think the dry-fire thing, while an issue, is overstated in normal springers.

Total amateur metallurgist/gun designer time.

I appreciate that delicate mechanisms are vulnerable to abuse. But complex non-delicate ones don’t have to be if they are well-designed and made of the correct materials.

I am no expert, but I have had a number of Giss guns pass through my hands. I have the irreparable remains of one in bits in a box somewhere where the cog-wheel lugs have been badly sheared off.

But:

- I don’t know how much abuse that thing went through before they broke.
- I don’t know if it developed major timing issues through seal degradation, causing the small cog teeth to suffer excessive stress and strain; almost certainly it did (the seals were cottage cheese).
- The cog teeth are stress risers, and thus likely to wear/break under extended normal use anyway.

Attempted conclusions:

- A major timing/cycling issue is seal degradation. Use good seals.
- Design in resilience against “uncushioned cycling”.
- As far as possible, design out stress risers, including selecting the right steel(s) (composition, tempering/hardness/toughness).
- From the above, and testing, set a required maintenance interval of pellets fired between services.
- Much as repeat business from factory servicing may be attractive, it’s also a commitment and a hassle. Consider designing in as much user/jobbing gunsmith serviceability as possible.

Just random musings. Hope they help.

And, as ever, good luck!

[norris]

Is the action on a sledge?
Have you thought of doing a recoiling version?

I would be very interested in either version but a springer that doesn't recoil just seems wrong to me.

[norris]

Please use an Anschutz barrel.

[Travis299]

FWIW, this is the sound/recoil for my HW95L .22 after an ARH tune and a GPL-205 lube. Rifle average of 15 shots of 716 FPS using H&N FTT 14.66s.

https://youtu.be/bywPFmB2_ZM

[cooper_dan]

In general, I think the dry-fire thing, while an issue, is overstated in normal springers.

Total amateur metallurgist/gun designer time.

I appreciate that delicate mechanisms are vulnerable to abuse. But complex non-delicate ones don’t have to be if they are well-designed and made of the correct materials.

I am no expert, but I have had a number of Giss guns pass through my hands. I have the irreparable remains of one in bits in a box somewhere where the cog-wheel lugs have been badly sheared off.

But:

- I don’t know how much abuse that thing went through before they broke.
- I don’t know if it developed major timing issues through seal degradation, causing the small cog teeth to suffer excessive stress and strain; almost certainly it did (the seals were cottage cheese).
- The cog teeth are stress risers, and thus likely to wear/break under extended normal use anyway.

Attempted conclusions:

- A major timing/cycling issue is seal degradation. Use good seals.
- Design in resilience against “uncushioned cycling”.
- As far as possible, design out stress risers, including selecting the right steel(s) (composition, tempering/hardness/toughness).
- From the above, and testing, set a required maintenance interval of pellets fired between services.
- Much as repeat business from factory servicing may be attractive, it’s also a commitment and a hassle. Consider designing in as much user/jobbing gunsmith serviceability as possible.

Just random musings. Hope they help.

And, as ever, good luck!

All good valid points.
From the start I've been designing this rifle to be much more 'user friendly' than other recoiless springers. Power adjustment is incredibly simple. As is the piston timing. There is protection against dry firing. The seals/springs are all off the shelf parts from existing guns.
I've had to accept a slightly lower efficiency than I originally wanted (to make the above possible), but engineering is always a compromise.
The planned service interval is 30,000 shots. Not sure if I can reach that yet, but that's the goal!

[cooper_dan]

Is the action on a sledge?
How you thought of doing a recoiling version?

I would be very interested in either version but a springer that doesn't recoil just seems wrong to me.

Its a geared system, so no sliding sledge.
I could do a recoiling version, but recoiless will always be my main aim. I think recoiless break barrels are about as good as it gets. Diana mod 60/65/66 are probably my favourite rifles. Maybe I'm weird like that though

[gunstock]

Best of British Dan keep it going

[mdunn]

Is it still going?.Atb mick

[WILBA]

Any update dan?

[cooper_dan]

This is definitely still going but unfortunately I am being let down yet again by UK suppliers/machine shops
The main cylinder of the action was months late and when it finally arrived had to go straight back again because it wasn't right.
I have most of the parts on order or already here. Just need to re-order some laser cut brackets because my current supplier have upped the price beyond what I think is reasonable.

I am starting a new job on 1st November and leaving my current job on 6th October. So my plan is to have everything in place to build three actions in that gap. That will be all the brazing, assembly, testing etc.
These three actions are re-designed versions that should fix all the issues I found in the first prototype.

Unfortunately if you have a limited budget and only want to make three prototypes, it's incredibly difficult to get anything done.

[evert]

....

Unfortunately if you have a limited budget and only want to make three prototypes, it's incredibly difficult to get anything done.

Maybe consider making all the parts yourself?

[TonyL]

Best of luck, Dan. I can just about appreciate how difficult it might be to get such a project off the ground......I know how difficult it was all those years ago for Steve Thornley of Kestock Conversions to try and turn the less-involved Predator into a living, breathing reality, designing, re-designing, out-sourcing, co-ordinating etc.......and those financials......especially in today's environment with escalating costs at every step......

The very best of continued luck with this and the new job.

[cooper_dan]

Maybe consider making all the parts yourself?

I'm a design engineer through and through. I can design anything in CAD and do any analysis work. But I don't have any machinery or skills to machine parts myself.
I could buy some kit and learn, but that would be just as expensive and time consuming. Don't think I could fit that around a full time jobs nd family etc

[cooper_dan]

Best of luck, Dan. I can just about appreciate how difficult it might be to get such a project off the ground......I know how difficult it was all those years ago for Steve Thornley of Kestock Conversions to try and turn the less-involved Predator into a living, breathing reality, designing, re-designing, out-sourcing, co-ordinating etc.......and those financials......especially in today's environment with escalating costs at every step......

The very best of continued luck with this and the new job.

Thanks. It turns out that trying to do everything yourself (design, analysis, purchasing, financials etc etc) is verging on a full time job, but without any pay so I have to keep going to the actual full time job too!