Patterned my Hatsan MPA, questions-solved!

weasel1

weasel1

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A couple of weeks ago I went out with a friend to shoot some clays. Despite me using my tacticooled shotgun, I did ok. Never counted, but I was hitting them at least 75-80% of the time. One thing I noticed, while I was hitting them, I never turned one into dust. I got a piece of it and that's about it. So today, I decided to pattern my shotgun. I used #8 shot and a mod choke. @40 yards, only 23% were in the 30" circle. @25 yards, things improved to 63% (an expected improvement). I also tried an extra full extended turkey choke. @40 yards, I had 38% in the 30"circle. Needless to say, I was a bit shocked. I can't believe I hit any clays at all and I can believe the pattern is so poor. Some of you may be wondering, chokes? How'd he do that on a Hatsan MPA? Well, a while ago, I made this:

IMG_20180904_152837.jpg


It's made from a piece of shotgun barrel that was threaded for Rem chokes. I'm starting to think that my barrel extension is the problem. And no, I haven't compared it to straight cylinder bore (I need to find another giant target to hit). Am I correct in thinking that the pattern is as poor as it is? Would things improve if I sent the barrel away to get threaded and toss my barrel extension in the garbage? Although I don't posses a whole lot of knowledge regarding shotguns, to me, v the patterns are suggesting that I'm going to be using my turkey choke for partridge. Before anyone asks, the only other shotgun in the house is a 20ga that is my daughter's. The lop is a wee bit short.
 
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Try different ammo. I have a .650 ext turkey choke that patterns number 8 shot pretty openly. It was designed for #5 and patterns almost to tight with 5s
 
I’ll bet your barrel extension is part of the problem, I would look into getting your factory barrel threaded if you can. Sounds like you’re on a budget so that’s what I’d do. How is the extension attached by the way?

Trying different ammo is a good suggestion, it really can change the way things pattern especially if you have a flight control wad in the mix.
 
Butcherbill said:
I’ll bet your barrel extension is part of the problem, I would look into getting your factory barrel threaded if you can. Sounds like you’re on a budget so that’s what I’d do. How is the extension attached by the way?

Trying different ammo is a good suggestion, it really can change the way things pattern especially if you have a flight control wad in the mix.
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The extension threads onto the barrel. I just remove the factory flash hider and screw this on in place. I still have to try my turkey ammo and I'll look into other target ammo to test.
 
It’s externally threaded from the factory I take it, do you know the thread pitch? If you google up Saiga shotgun muzzle adapters you should be able to find the choke adapter, it threads on an externally threaded barrel and then the choke threads into it. I have a short 870 barrel with this set up, takes winchokes. 14” barrel and a full choke patterns pretty nicely at 20-25yrds, nice and tight at 15y and under. I’m going to hunt grouse with it this year, 30y would be my safe limit with it I think. Well within the usual ranges I catch grouse at.
 
Butcherbill said:
It’s externally threaded from the factory I take it, do you know the thread pitch? If you google up Saiga shotgun muzzle adapters you should be able to find the choke adapter, it threads on an externally threaded barrel and then the choke threads into it. I have a short 870 barrel with this set up, takes winchokes. 14” barrel and a full choke patterns pretty nicely at 20-25yrds, nice and tight at 15y and under. I’m going to hunt grouse with it this year, 30y would be my safe limit with it I think. Well within the usual ranges I catch grouse at.
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Correct, it is externally threaded. Unfortunately the Saiga stuff won't fit. Believe me, I looked into it and I would have gone with a ready made solution. I was fortunate to know a couple of really good machinists to help me sort the adapter out. My Hatsan has a M21.5x.75 threads and the Saiga is M22x.75. That said, I guess there isn't much stopping me from chopping the treads I do have and re-threading the barrel to the same pitch as the Saiga. Between myself and the folks I know, it should be relatively easy to do. Might turn out to be the best option ( besides sending my barrel out to TacOrd.

EDIT: I just measured the outside dia of my barrel. First I'd have to cut off the existing threads. Measuring the barrel just back from where the threads would be cut is only 21mm. So, the Saiga option is gone :-(
 
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If that’s the case get a Saiga style adaptor turned on a lathe for rem chokes and the hatsan threading, honestly a choked 20” barrel is plenty for upland game if you know your distance limitations. I’ve shot more grouse with my 20” fabarm and a mod choke than anything else, throws right patterns and 9/10 times it’s head shots.

If you have machinists friends they should be able to turn something from aluminum round bar, if you need good pics and measurements of mine just pm me and I can give you any you need.
 
The only problem I have with my machinist buddies is that neither are gunsmiths and neither have the proper reamers/taps for chokes. I might have to re-work what I already have. All else fails, the barrel goes to Casey.
 
Although I can't comment on what affect your barrel extension might have on your patterns, every different shotgun barrel, even those of the same manufacture, will shoot a specific load differently. Every different shot load, even those from the same manufacturer, shoot differently in the same barrel. I believe you have two choices, first is to experiment with the dozens of different loads that are available until you find one that patterns well from your barrel, the second is to purchase a Pattern Master choke, which will definitely have a positive effect on your patterns.
 
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weasel1 said:
Correct, it is externally threaded. Unfortunately the Saiga stuff won't fit. Believe me, I looked into it and I would have gone with a ready made solution. I was fortunate to know a couple of really good machinists to help me sort the adapter out. My Hatsan has a M21.5x.75 threads and the Saiga is M22x.75. That said, I guess there isn't much stopping me from chopping the treads I do have and re-threading the barrel to the same pitch as the Saiga. Between myself and the folks I know, it should be relatively easy to do. Might turn out to be the best option ( besides sending my barrel out to TacOrd.

EDIT: I just measured the outside dia of my barrel. First I'd have to cut off the existing threads. Measuring the barrel just back from where the threads would be cut is only 21mm. So, the Saiga option is gone :-(
Click to expand...

Props to you for figuring out the thread size. What a weird size eh. I own a m22 tap now. Hah
 
Funny thing, I own an M22x.75 tap as well. Bought it when I thought that's the size I needed. It was a bit of a challenge to measure it right. Good thing I had some help!
 
I fixed it !! I shortened the barrel extension so that the choke would be as close to the muzzle as possible. My percentage with the mod choke went from 23% to 50% at 40 yards! At 25 yards damn near the whole load landed in my 30" circle (94.5%)! The turkey choke worked well too. Almost the whole load in a 12" circle @25 yards. I think at this point there isn't much room for improvement, besides maybe trying different chokes and ammo. Now to sit and wait patiently for partridge season to open...
 
Good job, sounds like you got it patterning a lot better. I’ve always found a 20” barrel to be the most versatile for upland hunting, long enough to shoot out to 30-40y and short enough to walk in thicker woods.
 
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