GTA
All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Topic started by: GoneShootn on March 22, 2016, 05:52:33 PM
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I have been having accuracy issues with both .177 and .25 models of AT44, and, using a video camera, I have determined that, at least in the .177 so far, the pellets are spiraling so that it is obvious, even at the 29 yards maximum range that I can get in my back yard. In the .177, I am using JSB Heavies at 940-970 FPS, but I had issues, also, at velocities from 870-910 FPS.
A couple of (maybe dumb) questions:
1. Are PCP accuracy issues always (or nearly always) due to pellet spiraling so that this new information is not nearly as useful as I might have at first thought?
2. When it is verified that the pellets are spiraling, is it always due to velocity too high?
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“Death spiral” at such short range is not normal. Isn’t uncommon at long range with some pellets (even highly respected pellets with some barrels), but at less than 30 yards?...somthing ain’t right.
SUSPECTS:
1. Dirty fouled barrel.
2. Bad crown (and if you are using a brake/ LDC, they it without the brake/ LDC).
3. Burr at the barrel transfer port nicking/slicing the pellet on loading. (load one, then remove the mag and push it back out the barrel from the muzzle and take a hard look).
4. Misaligned magazine (even though it’s a PIA, for a test, load the pellets single shot…even if you have to carefully use tweezers.)
5. Pellets just not compatible to that barrel. “Everyone” else might rave about them, but the barrel has the final say-so.
6. Worst case, if you want power in a .177, try the 13.4 or 16.2 JSB’s. Will be slower, but migt be worth the step-down in speed for the weight.
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when I first got my Hatsan AT44 .22, I went through 8 brands pellets in different weight. not thing worked even in 10 or 15 yards. all groups were at least an inch wide. until I try cheap Crossman Dome 14.3 grn, I can get 3/4 up to 60 yards. at 30-35 yards on a brenchrest, I shoot 10 pellets in the same whole!! keep trying different samples, you gun will find pellets that work best for its barrel
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“Death spiral” at such short range is not normal. Isn’t uncommon at long range with some pellets (even highly respected pellets with some barrels), but at less than 30 yards?...somthing ain’t right.
SUSPECTS:
1. Dirty fouled barrel.
Had just cleaned the barrel really well while removed. Patches and WD40 only, no brush.
2. Bad crown (and if you are using a brake/ LDC, they it without the brake/ LDC).
I can't do a crown on the .177, but if the .25 proves to be doing the same, then I can crown it. I guess I could do the brass screw thing on the .177. Would be a last resort, though.
Also am using LDC/moderator by BWalton. Just FYI, this one is for the .25 and am using on the .177, as well. Trying without the LDC is a good suggestion but do not know when I can do that. Can't do it at my house, so would have to load up everything, including table and stool, and head to the country. Can't do that in just an hour or so. Good suggestion, though, so will do when I can.
3. Burr at the barrel transfer port nicking/slicing the pellet on loading. (load one, then remove the mag and push it back out the barrel from the muzzle and take a hard look).
With barrel out, I have loaded a pellet and pushed it all the way through. Looked good to me and all the marks uniform. Of course, I am no expert.
4. Misaligned magazine (even though it’s a PIA, for a test, load the pellets single shot…even if you have to carefully use tweezers.)
Will try.
5. Pellets just not compatible to that barrel. “Everyone” else might rave about them, but the barrel has the final say-so.
I need heavy pellets and have tried JSB Heavies, Crosman Heavies, and Barracudas. Also JSB Monsters. Does best with JSB Heavies.
6. Worst case, if you want power in a .177, try the 13.4 or 16.2 JSB’s. Will be slower, but migt be worth the step-down in speed for the weight.
Doesn't like JSB Monsters. Haven't tried the 16.2, though.
Great input and suggestions! Thanks.
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when I first got my Hatsan AT44 .22, I went through 8 brands pellets in different weight. not thing worked even in 10 or 15 yards. all groups were at least an inch wide. until I try cheap Crossman Dome 14.3 grn, I can get 3/4 up to 60 yards. at 30-35 yards on a brenchrest, I shoot 10 pellets in the same whole!! keep trying different samples, you gun will find pellets that work best for its barrel
When I first got the .177, I tried a lot of pellets via a pellet sampler, and it didn't like any of the lighter pellets. The JSB Heavies were the best of the lot. Of course, it was shooting hot - probably over 1000 FPS with the lighter ones. I hadn't tried to lower the velocity any at that time.
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The hand-tool recrown (brass screw method) is as good as the care that goes into doing it...and if all the other possibilities don't fix the problem, what do you really have to lose by trying by that point?
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It is real hard to say what the problem is, I would try the .25 Kings at 880fps and the .177 I would drop down to 850 using the 10gr pellets..When you get a chance see what it does without the LDC, but I do not thing it is the LDC seeing that the holes are super big for a .177 Has to br barrel related...see if the oring is there at the end of the barrel at the breech end.
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All good advice thus far. But here's my 2 cents.
As pellets leave from a rifled barrel muzzle they are spinning on their axis, & it does not take much to make them corkscrew after they have left the muzzle. A slight deformity imprinted on them or a minor lack of uniformity on the edge of the crown can cause this effect just as easily as a major one. Higher velocity should only amplify whats already happening, & shooting slower will reduce the effect even to the point you may not notice it, but not eliminate the issue entirely.
If you can, I suggest send it back to wherever you bought it & let them resolve the issue & send it back to you. If that's not an option, then there are a few things you can try. Now it's not easy to tell what the immediate cause of the problem is without being able to see the barrel, but once you are 100% certain all your pellets are spiraling regardless of their weight or speed here's a couple things that might be the cause.
Possibly your breech oring is bad. If so change it & see what happens.
Possible burr on the edge of one of the lands in the barrel, push a pellet through from the breech to the muzzle & see if there are any marks on it that stand out as different. If there are, a few passes with some metal polish should remedy this.
A burr on the air inlet inside of the barrel, carefully polish it out if so.
A bad crown or burr on the crown, either re-crown the barrel or try to polish it out.
Magazine misalignment, single load the gun & if the sidelever & bolt probe closes smoother this way there may be some minor alignment issues.
If after trying those things the problems still persist, then it's the barrel & you could just order a replacement or decide where you want to go from there.
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as far as the 177 I think one reason can be the pellets are just going to fast. it is easy to slow it down by turning the hammer spring. baxter has a video on u tube shows how to do it and he has a good style of explaining it and there are others also on the same subject
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I kinda had the same problem .
I tried a lot of stuff but accuracy just wasn't very good.
As last resort I bought a new barrel from Hatsan.
And before I even fired the 1st shot I knew I'd found the problem. Before the new barrel I could feel the pellet being loaded when I'd cycle side lever, but after putting new barrel on I cycled it and honestly thought I'd forgot to load the clip.
Can't feel anything now when I work lever.
I don't think the other barrel lined up right , but it was a tighter fit. Also noticed the 2 set screw holes to lock barrel in place was just a little off , new barrel is right on the money . and now my gun shoots like all the reviews I had read before buying it . maybe nothing to do with your problems but thought I'd share .
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It is real hard to say what the problem is, I would try the .25 Kings at 880fps and the .177 I would drop down to 850 using the 10gr pellets..When you get a chance see what it does without the LDC, but I do not thing it is the LDC seeing that the holes are super big for a .177 Has to br barrel related...see if the oring is there at the end of the barrel at the breech end.
I don't think it's the LDC, either, but I'm going to try without just to be able to eliminate that.
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I have a question for anyone who has an AT44. When I close the bolt on my Marauder, it goes directly into the center of the chamber. On both of my AT44s, though, the bolt apparently first touches the bottom of the barrel and is pushed upwards very slightly, almost imperceptibly, as it enters the chamber. Is that normal for these rifles?
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hwve you tried changing up the speed at which you are shooting?
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No Jere, thats not normal & could most likely be the source of your accuracy issue. the bolt probe should move only forward & backward when you open & close it. If theres any kind of wiggling with the probe it wont seat every pellet the same way in the breech consistently.
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First thing I would try is turning the velocity back to approx 900 fps or less.
Try some h&n barracudas as they shoot very well out of my sons at44 at around 870 fps.
My own at 44 in 22 cal is set for 900 fps and it will consistently shoot 1 inch groups or better at 50 meters.
I fitted an fx muzzle flip to mine and that also seemed to help accuracy.
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hwve you tried changing up the speed at which you are shooting?
Sorry, I thought I had answered this. Yes, I have. It wasn't scientific, but I plugged all valve holes but one. I didn't have the chrony or camera running, but it must have slowed it way down. No improvement in groups. If I could find my .25 pellet sampler, I would try slower speed with several pellets, so may do that later.
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Day of the Twisters!
I spent most of yesterday in the country fooling with the .25 and .177. I couldn't find my .25 sampler, so I could only try JSB Kings, H&N Barracudas, and Benjamin domes. With the .177, I tried 5 or 6 pellets. In both guns everything spiraled, with or without the LDC. Some pellets more than others, of course, but all did. A few days ago, I recrowned the .25, but no improvement noticed. The .25 is at about 860 FPS with JSB Kings, and the .177 is at about 960 FPS, with JSB Heavies. I'm glad, at least, to know that it is not all due to by technique and ability and that it is not the scopes, either. Results were interesting, but I'm not sure where to go from here.
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No Jere, thats not normal & could most likely be the source of your accuracy issue. the bolt probe should move only forward & backward when you open & close it. If theres any kind of wiggling with the probe it wont seat every pellet the same way in the breech consistently.
Could explain why I am getting the results I am with both guns. See Day of the Twisters above. I haven't yet tried the suggestion to hand load with tweezers, but I may try that next. Off-center probe would affect even that, though.
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yup, a misaligned or wobbly probe will affect accuracy whether you single load or use the mag
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It is real hard to say what the problem is, I would try the .25 Kings at 880fps and the .177 I would drop down to 850 using the 10gr pellets..When you get a chance see what it does without the LDC, but I do not thing it is the LDC seeing that the holes are super big for a .177 Has to br barrel related...see if the oring is there at the end of the barrel at the breech end.
I just went through the same problem with my .177 S510 the LDC (not yours) was made for a .25 the S510 is a single hole rifle out past 25 yards when I installed the LDC I could not predict where the pellet was going at 10 yards. I found lead shavings inside the LDC . A little judicious work with a rat tail file and problem was solved. The S510 is fairly quiet even without the shroud so no problem for me to shoot it in my basement. Long winded way of saying try looking inside the LDC after it is removed from the rifle and see if any shavings shake out also look in side the bore of the LDC for evidence of damage from the pellets
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It is real hard to say what the problem is, I would try the .25 Kings at 880fps and the .177 I would drop down to 850 using the 10gr pellets..When you get a chance see what it does without the LDC, but I do not thing it is the LDC seeing that the holes are super big for a .177 Has to br barrel related...see if the oring is there at the end of the barrel at the breech end.
I just went through the same problem with my .177 S510 the LDC (not yours) was made for a .25 the S510 is a single hole rifle out past 25 yards when I installed the LDC I could not predict where the pellet was going at 10 yards. I found lead shavings inside the LDC . A little judicious work with a rat tail file and problem was solved. The S510 is fairly quiet even without the shroud so no problem for me to shoot it in my basement. Long winded way of saying try looking inside the LDC after it is removed from the rifle and see if any shavings shake out also look in side the bore of the LDC for evidence of damage from the pellets
Made for a .25 and still clipping? Goodness.
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It is real hard to say what the problem is, I would try the .25 Kings at 880fps and the .177 I would drop down to 850 using the 10gr pellets..When you get a chance see what it does without the LDC, but I do not thing it is the LDC seeing that the holes are super big for a .177 Has to br barrel related...see if the oring is there at the end of the barrel at the breech end.
I just went through the same problem with my .177 S510 the LDC (not yours) was made for a .25 the S510 is a single hole rifle out past 25 yards when I installed the LDC I could not predict where the pellet was going at 10 yards. I found lead shavings inside the LDC . A little judicious work with a rat tail file and problem was solved. The S510 is fairly quiet even without the shroud so no problem for me to shoot it in my basement. Long winded way of saying try looking inside the LDC after it is removed from the rifle and see if any shavings shake out also look in side the bore of the LDC for evidence of damage from the pellets
we are still looking at very tight tolerances over an extended length and a couple of areas where small errors can be additive and so anything can and does go wrong at times unless the builder has the rifle to match up to the LDC and test fire for proper alignment on the rifle
Made for a .25 and still clipping? Goodness.
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Turned out I never got a sampler for the .25. Instead, I bought JSB Kings, Benjamin Domes, H&N Barracudas, and Beeman Kodiaks (look the same as Barracudas), because most rifles seem to shoot one of these well. So I just ordered a bunch more pellets for the .25. In the meantime, I am going to video the bolt probe lift issue and will post it here for opinions. Looks to be about 1 mm of travel, but I haven't yet measured. I don't mind spending the time, spending the money, and doing the work so long as there is progress, but, as yet, there has been little. At least now, however, I know it is the rifles and not the scopes or me. We'll see how the new pellets do. Here are the ones I ordered:
* H&N Field Target Trophy 21.06 gr
* H&N Spitzkugel 24.85 gr
* JSB Predator 26.00 gr
* H&N Silver Point 24.38 gr
* JSB Heavy MKII 33.95 gr
* H&N Excite Coppa-Spitzkugel Pellets 24.54 gr
Thanks to all for the help.