New Blunderbuss

[neutron619]

My new Hatsan arrived today. It's a standard 20 bore semi although I was pleased to find it's had steel proof done when I looked at the marks. I'll probably play around with it for a couple of years and pass it on to my boy when he's big enough.

One thing is seriously puzzling me though. The proof house have marked the barrel "15.6" (= .614"), which is roughly what I'd expect. What I wasn't expecting though, was extended chokes (as opposed to flush) and then in some very odd sizes.

There's a choke marked "half" which the calipers have at 15.66mm (.617"), a "quarter" choke at 15.87mm (.624") and a "cylinder" all the way out at 16.05mm (.631"). All three are wider than the bore size - which I think technically makes them spreader chokes and the gun, if I use them, a blunderbuss!

The other two are slightly tighter than the bore - the "three-quarter" is 15.44 (0.607") and the "full" is 15.11mm (.594") which isn't much constriction, even in a 20 bore.

Meanwhile, the back ends of all of the tubes are in the range 16.35mm-16.43mm (.644"-.647") meaning there's a big "step" from bore diameter to the start of the choke - nearly half a millimeter all the way round.

After all of that, I assumed my calipers were broken, but they seem to be giving consistent / correct readings off other "known" measurements.

Don't get me wrong - I'll start with the half choke and see what it actually does on paper and in the field then tighten / loosen as appropriate. I'm just saying I've never seen such a wacky set of measurements on a gun before.

Anyone have any thoughts they want to share about Hatsans (this is my first) and "quality control"? I did read an old post here from someone who said theirs measured closer to a 16 bore - I can well believe it after today...

🤔

 

[humperdingle]

Hatsan 12 bore semi auto was my first gun … was alright, given it cost under £300 new at the time!

I got the synthetic, then a wood  stocked version, which had disappointing woodwork - It started to peel whatever coating was on it.

Both worked well but tbh they weren’t even run-in by the time I bought a Beretta as a replacement.

[Ultrastu]

That's a bit of a worry .as I have a .410 hatsan on order and that comes with multi chokes also .

 

[Ultrastu]

Did you manage to actually  measure for yourself the bore diameter  .? It maybe wider than the proof house says or at least wider going via your measuring tool ? 

[neutron619]

1 hour ago, Ultrastu said:

Did you manage to actually  measure for yourself the bore diameter  .? It maybe wider than the proof house says or at least wider going via your measuring tool ? 

Nope - my calipers aren't big enough, but generally I'd trust the proof house to measure it right. Unless someone was doing a batch of 20's and couldn't be bothered to change the numbers between guns...

The appearance, when looking down the barrel with the choke in seems to match the measurements. An obvious "lip" before the choke. I've got a calibration gauge / block somewhere - I'll dig it out later and check the calipers again.

All that said, if I can get the pattern I want out of it, with one of the chokes, with one of the candidate cartridges, it'll do. All these numbers will mean nothing if it works.

[Stonepark]

1 hour ago, Ultrastu said:

Did you manage to actually  measure for yourself the bore diameter  .? It maybe wider than the proof house says or at least wider going via your measuring tool ? 

Proof house measure the bore 6 inches in front of the chamber, might be worth measuring bore inch behind the choke step in case they have back bored the gun from the muzzle.

If you do have a big step, an aftermarket choke tube by Teague may be the answer.

[vmaxphil]

You may find when you pattern the chokes that with modern cartridges it will give you a half choke pattern as in so many pellets in a 30" circle but the choke maybe a larger diameter 

[Fellside]

1 hour ago, Stonepark said:

If you do have a big step, an aftermarket choke tube by Teague may be the answer.

Agree. I find Teague chokes measure out to within 4 thou of barrel diameter (for my Browning anyway). With this and the continuous taper they produce lovely patterns. I really like them. Think Hatsan use the Remchoke type (?). There must be a few aftermarket choices available. Perhaps an extra little treat from the OP’s pocket money - a new shiny choke. Which one though……? 

[old'un]

I wonder if the chokes work like recess or jug choke where a section of the bore is opened up near the muzzle allowing the shot to expand, it is then compressed as it leave the muzzle by the choke, this would then explain the back end of the chokes being .644"-.647" and the full choke being .594” giving you a constriction of approximately .043”.

[Stonepark]

14 minutes ago, Fellside said:

Which one though……? 

I often find the best (most consistant and evenly distributed) patterns (not necessarily the longest range) are Improved Cylinder or Light Modified, though saying that my code black goose tube (nominally Improved Modified - 3/4 choke - but throwing 62.5%  - Light Improved Modified) throws superb evenly distributed 40 yard patterns with most cartridges.

[neutron619]

40 minutes ago, Fellside said:

Agree. I find Teague chokes measure out to within 4 thou of barrel diameter (for my Browning anyway). With this and the continuous taper they produce lovely patterns. I really like them. Think Hatsan use the Remchoke type (?). There must be a few aftermarket choices available. Perhaps an extra little treat from the OP’s pocket money - a new shiny choke. Which one though……? 

I'd be happy to buy one (I prefer flush chokes anyway, rather than flashy silvery dangly bits!) but I'm not sure if Teague cater for 20ga Hatsans (although I've noted the Remchoke comment).

19 minutes ago, old'un said:

I wonder if the chokes work like recess or jug choke where a section of the bore is opened up near the muzzle allowing the shot to expand, it is then compressed as it leave the muzzle by the choke, this would then explain the back end of the chokes being .644"-.647" and the full choke being .594” giving you a constriction of approximately .043”.

I had wondered if this might be what was going on. Although the constrictions are a bit of an odd selection if that is how it's intended to work and I do wonder what the effect of opening out, then re-crushing a wad full of steel pellets might be in terms of scoring.

In the end, I'll just have to find out, as and when I can get out to try shooting it.

[wymberley]

3 hours ago, neutron619 said:

Nope - my calipers aren't big enough, but generally I'd trust the proof house to measure it right. Unless someone was doing a batch of 20's and couldn't be bothered to change the numbers between guns...

The appearance, when looking down the barrel with the choke in seems to match the measurements. An obvious "lip" before the choke. I've got a calibration gauge / block somewhere - I'll dig it out later and check the calipers again.

All that said, if I can get the pattern I want out of it, with one of the chokes, with one of the candidate cartridges, it'll do. All these numbers will mean nothing if it works.

Yep, as ever, "the proof of the pudding".

Trust yourself and your tools.

Pre 'back boring', call it what you will, we would recognise 0.615". Across the pond, was the same but later this became 0.617" (Remington figures) and the European standard became 0.619" (equates to 15.72mm).

My oldish Beretta 56E is stamped 16mm (0.630) both and measures .630 up and .632 down. My 725 is stamped 15.9mm both and measures .629 up and .630" down. These measurements are taken 9" from the breech. The Beretta chokes are stamped ** and **** and measure .606" and .614 respectively. The Browning in house (DS) .610" and .621" and by Teague pretty much the same - there may be a thou' in it but not enough to concern me and I only have up to 5/8 anyway - got some for decoying ranges.

In short, it's anybody's guess

Edited January 25, 2023 by wymberley

[Fellside]

18 minutes ago, neutron619 said:

I'd be happy to buy one (I prefer flush chokes anyway, rather than flashy silvery dangly bits!) but I'm not sure if Teague cater for 20ga Hatsans (although I've noted the Remchoke comment).

I had wondered if this might be what was going on. Although the constrictions are a bit of an odd selection if that is how it's intended to work and I do wonder what the effect of opening out, then re-crushing a wad full of steel pellets might be in terms of scoring.

In the end, I'll just have to find out, as and when I can get out to try shooting it.

Yes agreed - not in to barrel jewellery either…..😁