Building a HW35LGV

[DNF]

Well done you must have the best hw35 in existence...


May I suggest that you and Tony form a custom air rifle shop and sell your creations to the world.

[Baxterbasics]

Well Folks

I've let this thread slip a bit due to computer connection problems.

And I will post a few more build up pictures when I get fully sorted.

But the good news is I now have the HW35LGV up and running.

I ended up with a 25mm X 65mm bore and stroke with a 3.5mm ID X 6mm long transfer port.

Using the original 12ftlb Walther spring with a 50mm preload here are the velocities in .22" after about 250 pellets.


Superdomes 605fps

Hobbies 635fps

I don't know if I could get this sort of power level in .177" yet but if a .177" barrel comes along I'll give it a go.


My shooting mad next door neighbour has had a few shots with the gun and wants to know how the hell I've made it near enough recoiless ?

So now I fully understand why Tony (Bigtoe) is so enthusiastic about sleeving down HW80s to 25mm.





All the best Mick

Well done Mick. I don't profess to have anything more than a rudimentary knowledge of how these things work-despite this, I have followed this thread with much interest I would love to shoot this rifle one day

[T 20]

65mm stroke with a full spring, bet thats a bit quick on the old lock time

It is

The gun is very close to the Bowkett short stroked FT HW77 conversion in spec as described in John Bowkett's Bowkett file article of May 1990's AGW --- repeated again in a two part article in 1996's AGW.

Without altering the piston rod on the Walther piston I ended up with the 65mm stroke in the HW35 giving 575fps, the stroke could have been increased to 71mm in the gun without any problems but I decided to just add 3mm of preload washers inside the piston to bring the velocity up.

I could probably increase the power a little more by using a thinner grease on the HW35 spring guide and opening out the hole in the guide (it's a very good fit on the Walther piston rod) but for now I'm just going to use it as it is for a while then strip it out for bluing.




All the best Mick

[bigtoe01]

Mick

Make sure to push some heavy pellets thru it, I noted as you increase preload with short stroke the power with the heavy pellets rises and the lightweight stay the same, this is why i went from 68 to 70mm stroke on the .22 80 so i evened out the the power with 2mm stroke and see 11.2ish with hobby and 19gr Baracuda hunter extremes so its quite a versatile rifle.

Did you put steel washers in the piston or plastic ones...interested in the weight?

[gibboj]

looking good mike , am i right in thinking with the fps your getting 600 -635 your hw35 is making about 11.7 flb on a 65mm stroke ? if so thats very efficant on a 25mm piston. i could not get my short stroked 70mm x 26mm past 10.3flb in .22 not even with a piston weight and 50mm of preload .went up to 11.3flb on a 75mm stroke easly though. do you think the very short transfer port suited the 65mm x 25mm it lookes like it to me ?
atb john

[T 20]

Mick

Make sure to push some heavy pellets thru it, I noted as you increase preload with short stroke the power with the heavy pellets rises and the lightweight stay the same, this is why i went from 68 to 70mm stroke on the .22 80 so i evened out the the power with 2mm stroke and see 11.2ish with hobby and 19gr Baracuda hunter extremes so its quite a versatile rifle.

Did you put steel washers in the piston or plastic ones...interested in the weight?

Hi Tony


So far I've only tried the gun with Superdomes, Hobbies, AA field and Napiers (both around 16grain) and so far the Superdomes give the highest power --- I'll try some Baracudas today and a few others.


Yes I used 3 steel washers in the piston Tony to give both preload and weight --- at one point BSA made a big thing of fitting piston weights to the new Supersport, like garlic bread, piston weights were supposed to be a taste of the future.


From the Bowkett files (1990) Mr Bowkett added a 50 gram weight to the 219 gram 77 piston when running a shorter stroke = a piston weight of 269 grams.

The Walther piston weighs about 257 grams so that's 12 grams short of Mr Bowkett's 1990 figure of 269 grams so I was happy to add a little more weight to the piston.

(The Bowkett files of 1996 show a different piston weight in the shortstroked 77 so I could be over Mr Bowkett's later piston weight)





All the best Mick

[bigtoe01]

Mines at around 35mm preload in the 80 .22 with with a shortened spring, after pushing 1000+ pellets thru the .22 it had gained in efficiency, remember 70mm stroke...Just again crushed another coil down in the spring, it actually feels like it is recoiling even less now.

Both this and the .177 are like 7.5J rifles to cock, one comment was they feel to weak to make the power...how far from the truth that is

[Baxterbasics]

Do you lads work on others rifles or just your own?

[thevoid]

Do you lads work on others rifles or just your own?

It has been known lol

[T 20]

Mines at around 35mm preload in the 80 .22 with with a shortened spring, after pushing 1000+ pellets thru the .22 it had gained in efficiency, remember 70mm stroke...Just again crushed another coil down in the spring, it actually feels like it is recoiling even less now.

Both this and the .177 are like 7.5J rifles to cock, one comment was they feel to weak to make the power...how far from the truth that is

Hi Tony

Unfortunately after another couple of hundred pellets the power has risen a little (12.6) so I'll have to pull a couple of preload washers out, but this is encouraging news in that converting the gun to .177" may work at 12ftlbs with the existing 65mm stroke.

Interestingly the gun gives maximum power with Superdomes and no other pellet I've tested comes anywhere near --- strangely as the gun is bedding in the velocity of Hobbies has dropped off so that they leave the gun at the same velocity as Superdomes.
Maybe removing some preload will also bring the power with Hobbies back up ?


Anyway I've realised I haven't posted any pictures of the finished gun so here we go.

Before:-

http://i1138.photobucket.com/albums/...Picture007.jpg

After (with altered spare cylinder):-

http://i1138.photobucket.com/albums/...0_12160039.jpg

She just looks like another knackered old HW35 until you take a look inside :-

http://i1138.photobucket.com/albums/...s/P1080227.jpg

http://i1138.photobucket.com/albums/...3022006724.jpg

http://i1138.photobucket.com/albums/...0_12160043.jpg

http://i1138.photobucket.com/albums/...0_12160044.jpg


There are still a couple of small tweeks to do on the gun but for now I'm quite happy with it.


But if anybody has a HW35E stock or a .177" barrel for sale I'd be interested.






All the best Mick

[coburn]

Out of interest when can we start sending you our 35's to get done. I've got an old knacker of a 35 in my loft at the moment and its ripe for this kind of conversion. (mind you its running at 10.8ftlbs with Superdome with some unknown square section spring in there)?

[Weasle]

Mick

What a fantastic project - it been an unmissable read

I have just fitted my 35 with a walnut stock in place of the original beech, and the lack of weight may be to its detriment. I will give it a good workout this week at the club and maybe Tony (Bigtoe) will give me his valued verdict

Keep up the good work

All the best

Steve ( ;-)>

[TonyL]

Superb project and enthralling read, Mick, well done!

Between your good self, Tony and the Technical Airgun Section, we are now getting some proper clarification on what works with our 12 ft.lbs spring guns. Up to fairly recently, I (and I'm sure many others) had many, many questions about what blueprint would work best. Now, we spring gun aficionados can see things in a different light and not a "black art". So many questions have been answered.

Again, brilliant, well done, chaps!

[TonyL]

My shooting mad next door neighbour has had a few shots with the gun and wants to know how the hell I've made it near enough recoiless ?

So now I fully understand why Tony (Bigtoe) is so enthusiastic about sleeving down HW80s to 25mm.





All the best Mick

In the not too distant future, I'm going to dust the Lazaglided 80 Bullpup down and get over to Tone's club and see what he thinks. As you say, as near as dammit recoilless and the sound is more akin to flicking a wooden jug, just a muted, hollow, "thunk".

[bigtoe01]

Mick

You have the same issue i do, superdomes are supremely efficient as are super H point, I would check for accuracy with domes and if they prove ok tune down to them,you need to get some 18gr JSB heavies and 19gr baracuda hunter extremes just to be sure. The gun will have become mores sensitive to head size on pellets now as mine has, H&N and RWS pellets are going to be best but stay with the smaller head sizes.

Great pics, looks just like a normal 35 from the outside