H135 bore mapping and associated issues

[Toxylon]

I’ve had a walnut-stocked, coil springed Hatsan 135 .25 cal (manufactured in 2020) for some years now, working on it and shooting it occasionally in my springer rotation, for a total approaching 1 000 pellets. The problem with it is it’s just not accurate. I’ve zeroed in on the problem as the barrel, or bore.

The H135 fits my frame and face well, the gun has a great balance and I like shooting it. In my opinion, the 135’s, in walnut, at the bigger cals and with the skinniest, barest barrel option, are well-designed magnums.

Early on, after break-in, I disassembled, deburred, re-sealed (with breech seal shim) and relubed the gun, making it shoot with spec power (41.7J  /  30.7 fpe with Polymags) and with exceptional consistency (10-shot spreads down to 3 fps with some pellets), so the powerplant is not to blame. But, standing offhand at 22 yards, I haven’t been able to keep Polymags or other pellets inside a 30mm bullseye with five shots, my minimum standing offhand open sights springer field accuracy treshold, not even close. So the setup is unusable as it is.

Recently, to crack the problem, I re-did some pellet pushing for the 135 bore, with experience and insight gained since the last time. First off, I re-cleaned the barrel really thoroughly, having been schooled on the tightly embedded filth Hatsan bores exhibit. Not having access to the airgun deep-clean standard JB Bore Clean here, I used oven cleaning foam, which some seasoned pros have used to get the factory / history gunk out of bores once and for all. It is designed to break up burnt -in grease, after all. I would repeatedly pull patches through the foam caked on top of an upright barrel’s breech to transfer the foam everywehere, then leave the barrel standing plugged on both ends for 30+ minutes, before a thorough washup / dryup.

The 135 bore did end up cleaner than it had ever been, and it needed that for the pellet pushing to have actual diagnostic value. I then chose the biggest-skirt, hardest-alloy .25 cal pellets I had, Benjamin .25 cals, since I already knew the 135 bore was pretty loose, and wanted to max the ‘radar ping’ the pellets would send from inside the bore.

The results were pretty drastic: after clearing a moderately contact-y breech block section, the pellets would travel with a very light contact out to about 4–6 inches off the muzzle, when they would start a sudden, extended freefall, with zero pellet-to-bore contact, being only stopped by the muzzle choke, and even then only barely, with the pellet heads halfway sticking out of the muzzle. The exact starting point of the freefall would depend on the individual pellet’s size (the Benjamins aren’t consistent), explaining the range above. Quality pellets fared even worse, with minimal contact at best, and very long freefalls.

I have heard many Hatsan barrels are like this, FWIW.

Picture a pellet carrying 30 fpe losing grip 100 % for a hand width+ before hitting a short, barely-there choke at whatever angle, and the lack of accuracy is no mystery. Of course, if the choke wasn’t there, this barrel would make for a total sawn-off scattergun.
See the pic for a pellet in the loose bore.

The problem is, H135 / 125 replacement barrels aren’t easy to get. My go-to place for Hatsan parts, Sharg Poland, has been out of stock for a long while. Further, there is zero guarantee a replacement barrel, fetching around 100 bucks with shipping, would be any better than my 2020 barrel. I could buy an older donor gun for a barrel, but they are never .25 cals around here.

I used to have a Walther Falcon Hunter .22 cal, made by Hatsan in 2008, that had an accurate barrel. I gave the gun to a friend, and at any rate, I don’t want yet another .22 cal magnum, I want a .25 cal.

[Toxylon]

For the time being, I decided to plow on with the loose barrel, for education if nothing else. I wanted to check the muzzle crown of my 135, having never seen it from under the molded front sight base. I tapped the front sight base off for a look. The murky factory crown looked a bit rough and also possibly a little off-center. This would / could explain the accuracy issue quite a bit.

Having never done a re-crown, this was a schooling opportunity. I used a domed brass screw hitched in a portable drill and coated with Permatex valve grinding compound (fine), and very little pressure and a forever changing circular pattern. The crown did turn out much cleaner and crisper than before. I know this cannot overcome an asymmetric crown. It’d be easier to create a new crown altogether, on a fresh muzzle surface. But this barrel doesn’t allow ANY shortening, as it would take out the miniscule choke and leave the rain gutter behind it in charge.

At this late juncture, I also switched the completely insufficient factory rear guide with a long custom steel guide gifted to me by Mikey quite a while back. The broken-in factory spring went on the guide with a hefty push, not quite tight enough, but I want to get a direct comparison between the factory and custom guides. I didn’t change anything else, or even extract the piston, to this end.

It’ll be interesting to see what’s the gun’s cycle and velocity now. Maybe, just maybe, accuracy improves some with the bore scrub and re-crown, too.

[eeler1]

Hatsans can sometimes benefit from de-tuning. Like your barrel, the tubes on a lot of them are not uniform so the piston fishtails or hops along making it hard to get consistent results.  Detuning makes the fishtail or hop less violent and calms down the piston. 

Another thing you might try, is to heat the muzzle to cherry red and then quench it in water.  Mark Gravelle in NorCal came up with the idea.  It’s a hillbilly way to get a choke and you have no control over it, but it will often help.  Basically puckers the end of the muzzle slightly and provides a short choke where there wasn’t one.  Last resort kind of procedure before you toss the bad barrel.

[mikeyb]

Very nice re-crown IMO. May help with accuracy issue, but I suspect not much.

Hope the steel guide improves the shot cycle for you :-)

Leaving work and typing on my cell phone for this post so can't go into detail but I have 2 suggestions to try before you give up on that barrel. Details soon... :-)

[Blowpipe Sam]

Subscribing.

I consider my .25 caliber mod 135 to be adequately accurate at 35 yards.  It's not as accurate as my .25 caliber mod 125 but the mod 125 runs at only about 28 FPE.  The mod 135 will shoot 1" groups at 35 yards with JSB Kings.  I suspect that would improve if I detuned the gun but it is running near 31 FPE right now and I decided that If I'm gonna hump that big heavy sucker through the thickets hunting I want every ounce of energy it can produce.

[Toxylon]

Jon,

Good point about the tube issues, but I don't think I have those. My 135 shoots with exceptional consistency, as far as velocities go. I would think a fishtailing / hopping piston wouldn't allow that.

Hillbilly choking indeed! I'll keep that in mind for the future.

[Toxylon]

I looked into one far-out way to deal with this.

I have a Xisico .25 cal barrel, prepped by Mike Melick. It bore maps superiorly to the Hatsan barrel. I bought it for my 350 Mag, but the breech block was out of spec in my German gun (too long). These days, I'm not so sure the 350 Mag makes for a swell .25 cal gun, anyway, while I know the H135 does.

Could I combine the Xisico barrel with the Hatsan breech block for a superior-barrel, superior-powerplant Franken-gun, hmmm?

Both barrels are 16mm, which is a first hurdle cleared. It seems Hatsan barrels are screwed into the breech blocks. I don't know what attachment Xisico uses, but the Xisico barrel is so long it could actually be sawed off at the barrel / block junction, taking a massive amount of work / headache out of the picture.

Still, getting the Hatsan barrel out of its block without distorting / destroying the barrel hole / tap inside the block (or the block itself), then tapping the Xisico barrel to spec, then arranging the heavy duty AND precision assembly of the two parts would be a massive entry into unknown waters for me, outside the hardware / tooling capability I have.

[Madd Hatter]

For the time being, I decided to plow on with the loose barrel, for education if nothing else. I wanted to check the muzzle crown of my 135, having never seen it from under the molded front sight base. I tapped the front sight base off for a look. The murky factory crown looked a bit rough and also possibly a little off-center. This would / could explain the accuracy issue quite a bit.

Having never done a re-crown, this was a schooling opportunity. I used a domed brass screw hitched in a portable drill and coated with Permatex valve grinding compound (fine), and very little pressure and a forever changing circular pattern. The crown did turn out much cleaner and crisper than before. I know this cannot overcome an asymmetric crown. It’d be easier to create a new crown altogether, on a fresh muzzle surface. But this barrel doesn’t allow ANY shortening, as it would take out the miniscule choke and leave the rain gutter behind it in charge.

At this late juncture, I also switched the completely insufficient factory rear guide with a long custom steel guide gifted to me by Mikey quite a while back. The broken-in factory spring went on the guide with a hefty push, not quite tight enough, but I want to get a direct comparison between the factory and custom guides. I didn’t change anything else, or even extract the piston, to this end.

It’ll be interesting to see what’s the gun’s cycle and velocity now. Maybe, just maybe, accuracy improves some with the bore scrub and re-crown, too.

How did you get the shroud off?

[mikeyb]

The old style coil spring Mod135 looks like this. No shroud.



I got one a few years back on a closeout/freeship sale ($120) from HatsanUSA. They had a few new (old warehouse) rifles they wanted to purge and they were all in 177, hence the sale.
I have not removed the front sight but assume it is a press fit(?)

********
Pretty certain the Hatsan barrels are pressed into the block and then pinned.



The barrel you describe seems to be a "bad" barrel as described by Mike E. in the link above. A new barrel may be the only solution.

********

I don't have a "freefall" barrel so the following suggestions are unlikely to help in your specific case.

1)  I acquired a new (not refurbished) Striker spring wood 25 cal which was giving me 2" random groups at only 30'. I completely tore down the rifle, deburred, cleaned, and relubed everything. Also improved the barrel lockup which I HOPED was the cause of the inaccuracy. With everything working as it should my groups were still bad. I tried many different pellets over a 6 month period and none would group better. In FRUSTRATION I gave the rifle a DEATH GRIP hold and fired off one last shot before putting it in the "for parts" bin. I thought I missed the target but the pellet actually punched out the black marker dot I was aiming at. Just lucky? Tried the death grip hold for 4 more pellets and all the holes overlapped!

The rifle was fine, it was my hold! THAT ONE SPRINGER in THAT CALIBER needed the opposite of the artillery hold. My theory is that the slow heavy 25 caliber pellet stayed in the bore longer than the smaller faster 22 and 177 pellets so the "loose" artillery hold allowed too much rifle movement before the pellet exited the muzzle. The firm hold allowed me to stay on target longer? That's just a theory. Regardless of WHY I can now shoot that rifle with enough accuracy to be useful.

2)  I have a loose (but NOT freefall) bore on a Mod125 25 caliber rifle. Rifle marks on a pushed pellet were very weak on the skirt and invisible on the head. I thought it would have accuracy issues. It did not. Heavy cocking force and almost painful shot cycle aside, I can get penny sized 10 shots groups at 30'.

Pellets captured AFTER being shot had deep crisp rifling marks on the "inflated" skirts and slightly visible rifling marks on the pellet heads.

*********
I never checked price or availability of Hatsan barrels from Hatsan USA. I figured they would come assembled into the block so fairly easy to replace. Getting another barrel from Hatsan is a risk since you "may" get another bad one(?)

I did some research a couple years back and found a Lothar Walther airgun blank in a caliber I "might" want someday. Cost was ~$140 shipped, so not cheap. I have some basic tools like a drill press, a wood lathe, and a hydraulic press. I do NOT have metal lathe so I thought replacing a bad Hatsan barrel with a Lothar Walther barrel would not be a realistic project for me to tackle. If you have access to a hydraulic press and a metal lathe then processing a blank barrel should be easy.

[Toxylon]

Mikey,

Thank you for the kind re-crowning commentary, the Ellingsworth link and the suggestions above!

I had no idea before yesterday that Ellingsworth somewhat routinely re-barrels Hatsans. In his videos, I have seen the results, but he hasn't gone into how the re-barreling is done. I suppose it involves hydraulic presses and sundry other tooling shop gear. I have none, neither access to one.

Ellingsworth's comment that it's about 50/50 whether you get a good barrel off the Hatsan factory matches my small personal sample so far. You Mike have tested way more Hatsan barrels than that and seem to have much better statistics.

A semi-local gun shop has LW airgun barrel blanks available. A .25 cal choked blank (a whopping 23.8" in length for PCP needs) fetches 170 buckaroos plus shipping, and you still need to cut and graft the blank into a prepped breech block. That's the price of almost three H125/135 barrels, with breech blocks, sights and all.

Based on my research, I'd have better chances with an older donor gun than with buying a new replacement barrel. The peak of Hatsan springer quality is some dozen years in the past. But too old is worse than present (Hatsans have been available here since 2005 or so).

I have heard on occasion that many Hatsan springers only shoot well with something bordering on death grip. I have shot my 135 with way harder grip than any of my other guns, but will test the death grip theory. There's nothing but time and pellets to lose.

Yes, my 135 is the basic model, which is the best model to me: lightest, prettiest, most foolprool, and easiest to maintain (bore cleaning). I also think the 10+ inch barrels of the Snipers etc. are too short for efficiency in ultra mag springers.

The front sight base is a press fit. I used a hardwood slat and a rubber mallet to pound the base off the barrel. There's simple knurling / ribbing under there, not the unfathomable re-shaping of the entire barrel front end, as on the H125's.

[Blowpipe Sam]

I have watched a few of that guy's videos and they are awful.  The dude's camera placement is dreadful.  A lot of the time you can't see what he's talking about.  His bench is a mess, it's difficult to see what he's doing and he's mush mouthed.  Maybe it's because I am a school teacher by avocation that this guy's sloppy work bothers me but after seeing how he tosses parts around I don't think I'd want him to work on my guns.  I guess the reason people recommend his stuff is because there's a lot of it and it's easy to find on line.

Trust me.  Look a little farther.  There's good (but obscure) content out there.  Better than that guy.

[splitbeing]

My suspicions you were a teacher by trade at some point are confirmed, Cap.  Nobody writes like you without being on the other side of a paper or project (well, maybe not nobody but not many).

[Blowpipe Sam]

My suspicions you were a teacher by trade at some point are confirmed, Cap.  Nobody writes like you without being on the other side of a paper or project (well, maybe not nobody but not many).

When I was going to college to get my teaching certification I worked part time as a park ranger.  I found I preferred shooting muskets and cannon, driving swamp buggies and riverboat tours, and leading nature hikes to lecturing in a classroom.

[Toxylon]

Luddite as teacher - an interesting concept. What do you teach? How to live off the grid?

[Madd Hatter]

There's tech involved in living off grid, believe me unless you want to just use candles for light and burn wood for heat and cooking.

[Blowpipe Sam]

Luddite as teacher - an interesting concept. What do you teach? How to live off the grid?

I am a park ranger/environmental educator.  I teach biology and cultural history.  Lots of hands on demonstrations of primitive life skills.  Basic stuff like Flint knapping, basket weaving, rope making, balancing a checkbook.

Yeah it's a scam.  I've got these rubes fooled into thinking that I do something useful.  Beats working for a living.

A park manager up in Georgia caught me fly fishing one morning years ago.  I had a 12 inch brookie on the line when he popped out of the bushes and asked me what the heck I was doing.  I calmly replied that I was collecting samples for my 9:00 a.m. stream life class.  Carry on says he.

[Mossonarock]

A 12 inch brookie? That's like a once in a lifetime fish for a lot of people.

Back on subject: I'm a firm believer in death grip hold for these powerful hatsans, particularly firm shoulder placement. Its like the gun bounces off your shoulder which ends up pointing the gun in random directions. So, I press the gun tightly against my shoulder. That tightens up the groups by a lot.

[Toxylon]

Thanks Tim for the death grip user report. Good to see you here!

[Berserkeley Mike]

For the price you quote for new barrels, one could buy a refurb Mod 130 or 135/30 and swap barrels.  You'll get a nice QE barrel and shroud.  Sell the new gun with old barrel for so cheap that the new owner won't care, or save it in case you ever want to go Vortex.  If the new barrel isn't good, repeat until it is.

[Toxylon]

There are no refurbs here. The cheapest H125/135's available here outside individual used gun sales are well past the 200 mark. Most places ask around 300 these inflation days. Used prices can go down to 100, but it's rare, and much rarer still in .25 cal.

QE barrels are a no-go to me, for several reasons mentioned in this thread and detailed elsewhere. It has to be a full-length barrel of bare steel, no shrouds, no moderators.