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All Springer/NP/PCP Air Gun Discussion General => Air Gun Gate => Topic started by: TooJung2Die on October 23, 2014, 11:05:48 PM
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I shot the Diana 52 today hoping to get used to the recoil and find it's favorite pellet. I tried all different ways of holding it even just resting the forearm on a rolled up towel. After several hundred shots and a half dozen different pellets I began to think something is wrong. This doesn't shoot like any Diana I've shot. The best groups were 1.5" at 25 yards and most were much worse with wild flyers all over the place. I put the Leapers 4x32 AO back on the other spring gun. It's not the scope.
I had checked the crown before and was satisfied with the way it was cut at the factory. Today I used a bore light and looked inside. I think I found the problem. There are four grooves in the rifling just before the crown. This is probably unstabilizing the pellet just as it leaves the barrel.
Normally I would cut off the offending section of the barrel and recrown it. But this is a choked barrel and I don't want to eliminate the choke. What are my options?
Thanks,
Jon
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At the risk of stating the obvious, it appears to be a factory defect. If the gun is new (as opposed to new to you) your best bet may be to get a warranty replacement.
I have no idea how far into the gun the crown goes or whether it could be cut while preserving the choke.
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It's the Model 52 in my signature, Oct. 1992.
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Short of replacing the barrel polishing it with bore paste may be the only option. The lands in the rifling look pretty deep like all Diana's. It would be a gamble but maybe you can use some steel wool?
Bryan
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Push a pellet through with a cleaning rod to determine the length and location of the choke; you may be able to shave the end off the muzzle and still have a choke.
If that proves fruitless, you can try lapping the bore.
Before I replaced the barrel I'd cut it, recrown it, and see how she shoots. You never know, and at that point there's nothing to lose.
That being said, there are guys who have the equipment to re-choke a barrel. Probably cheaper than a new barrel, but I don't know that for sure.
Good luck, and keep us posted.
-Paul
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I would cut it, can't get any worse 8)
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try cleaning it up a bit with steel wool on a brass brush covered in jb bore paste. and if youre results don't get any better chop it.
Josh
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Good suggestions so far, personally I'd try & ascertain how far the choke goes by pushing a pellet through as suggested, and if it's long enough then chop the offending part off the barrel & recrown. If the choke would be destroyed by chopping then I'd probably first off melt some pellets & cast a lapping slug, then lap the barrel to see if the imperfections can be got rid of.
Failing that, I'd just lose the choke. it should shoot fine without anyway, as long as you make the cut precise & recrown it afterwards.
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Thanks for all the suggestions.
The choke starts about 3/4" before the muzzle. I wrapped some extra fine wet or dry sandpaper around a bamboo skewer until it fit snug in the end of the barrel. Worked it in and out for the first 1" of the barrel using light oil for lube until the scratches were gone. Then I applied JB bore compound to a few q-tips and polished the area I just sanded. I can still feel the choke when I pull a patch through the bore. The rifling grooves are slightly shallower at the muzzle.
It helped. Groups weren't noticeably better using RWS pellets (dome, wadcutter, pointed) but when I switched to Crosman ultra-mags 10.5 gr things started to improve. Still getting wild fliers. It seems to like the heavier, tight fitting heads of the ultra-mags but when a pellet with loose fitting head is shot it goes high and wild. The ultra-mags are the heaviest .177 pellets I have. My other two Diana's like RWS pellets. Not so this model 52 so far.
I'm going to have to practice some more with this 52. It has a very strong recoil despite it's weight, 10.5 lbs with the scope. It's not what I would consider to be a hunting rifle unless you can sit and wait for the quarry and shoot off a bag.
If I can't find the right pellet and hold combination I'll chop off the choke and see what happens. That will be a bit difficult because the end of the barrel is dove tailed for the front sight. Shortening the barrel will shorten the dove tail and the front sight won't be flush with the muzzle without further modification.
Jon
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I would recommend trying jsbs before you do anything else.
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If you use a scope why worry about the dovetail. If you go to some of the muzzle loading build sites they show how to cut a new dovetail with common hand tools. Just like they did in 1776. I have cut them and they are easy. john
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I would recommend trying jsbs before you do anything else.
Which JSB's? I tried JSB Exact 8.44gr. These have never been the best pellet in any airgun I own. Odd because they're usually highly recommended. I keep trying them though.
If you use a scope why worry about the dovetail? If you go to some of the muzzle loading build sites they show how to cut a new dovetail with common hand tools.
The barrel is sleeved and the sleeve is held in place by the front sight. I'll search for how to cut a dovetail as you suggested.
It looks like chopping the muzzle will be the next step. I'll have to shorten the barrel sleeve too. Tried some 10 shot groups using different pellets at 25 yards. Not very good at all. At this close range I expect all the pellet holes to be touching.
CP Light 1.2"
CP Heavy 1.4"
JSB Exact 1.6"
Superdome 2.4"
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Try jab 10.3s
Josh
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I found this to be the best for re-crowning a barrel. If you want to try it, look for it on line and get a few different sizes in fine grit. It does a good job.
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While a good shooting barrel does not need to have a choke......it goes a little deeper than that. It must be designed for it.
A barrel can be made to not require a choke, but barrels designed to utilize chokes are not going to shoot better with them cut off.
Choked barrels have rather "loose" groove diameters prior to the choke. The pellet will rarely ever leave the bore perpendicular in that situation.....because all it has to support the head is the lands. The best you can hope for is that it leaves consistently crooked.
Mike
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another thing I have done to not loose front dovetails is to counter bore the muzzle, in your case would be much better than chopping.
Josh
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I'm jinxed. Another air rifle with a bad barrel. >:(
I JB compound and rubbing compound polished the bore until I thought the rifling should be worn off. It is mirror bright but no improvement in accuracy. The problem is very evident when pushing a pellet through from the breech. It's snug, then loose, then a couple more snug spots, then it feels like the ridges of a washboard for the last half barrel to the choke. There is another slight loose spot just before the choke. Those grooves are not just at the crown. You can feel them for half the length of the barrel.
I priced a new barrel but the price is almost what a new Diana can cost. Has anyone slug lapped a .177 barrel? This might be a good candidate. Can't get much worse.
Doesn't Diana/Umarex have a lifetime warranty?
I should step away from this project for a while and work on something else. A little happiness with different project gun will motivate me to give it another go.
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Before you go cutting the barrel, have you checked all the stock screws to make sure they are tight, and all at the same torque?? How about the scope mount screws, and the scope ring screws?? I would try all those first. If you find it shoots better, take out one screw at a time and put LocTite blue on them. Then let it sit for 24-48 hours to cure, then try it again. I'll bet it shoots a lot better!! Just my 2 cents as a tuner who has seen it happen many, many times. Good luck - Lee aka the "Shootist"
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I'll buy it for scrap steel price if you get tired of fooling with it.
Josh
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Before you go cutting the barrel, have you checked all the stock screws to make sure they are tight, and all at the same torque?? How about the scope mount screws, and the scope ring screws?? I would try all those first. If you find it shoots better, take out one screw at a time and put LocTite blue on them. Then let it sit for 24-48 hours to cure, then try it again. I'll bet it shoots a lot better!! Just my 2 cents as a tuner who has seen it happen many, many times. Good luck - Lee aka the "Shootist"
I tried all that first. It's a bad barrel. Been through this too many times with other guns. More than my share. That's why I swear I'm jinxed. A new barrel fixed it when everything else wouldn't. That's not so simple with a fixed barrel gun like the 48/52.
I'll buy it for scrap steel price if you get tired of fooling with it.
Josh
That's mighty nice of you, Josh. ;) You get so you want to find a sturdy tree and make a horse shoe out of the barrel. Might even improve the accuracy. Plan B is to hold on to it and hope another 48/52 comes along that needs work and I'll have the parts. Then there's still the option of cutting the barrel.
Jon
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John - Thanks for the encouragement. Maybe a Chinese barrel will fit without too much machine work. I don't have access to a lathe. I've pulled out and re-installed barrels on break barrel springers. I can see that this barrel is press fit with splines on the barrel, no epoxy is evident.
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Hey Jon I held off just like cutting the barrel is a last resort the pre last resort to that is... (cause if you over do it can ruin the barrel?)
to try fire lapping once you feel you have no other option...
I did a mild fire lap on my 1377 with about 20 rounds and auto rubbing compound because of a groove that ran lengthwise down the barrel and it did the job I think there was just a very slight high spot because of it... it did not polish it all the way out but it didtake down the very slight ridge it caused.
I used a paper q tip and cut the tip off coated it with compound and put it directly in the barrel just past the beginning of the rifling using another qtip which I then used the other end of to clean the area behind the qtip in the barrel. the I loaded a 10.3 ultra mag and fired then 4 more pellets and then more compound and 4-5 more pellets then cleaned the barrel. it did polish the barrel and the scratch/groove while still there was lessened. I did another ten rounds and cleaned again and cleaned again the scratch was almost gone... I have put about a 500 tin thru since and can not see where it was... it did reduce 20 yard groups to about .5 from about .75 side rested...
Now what I did is not the usual use, it is supposed to help barrels like yours by taking down the high spots...
I fire lapped my long .22 barrels to polish them and it worked I used toothpaste for compound and about ten pellets same qtip method...
I know it did not hurt them...
So if you feel you have nothing to lose...
https://www.google.com/search?sourceid=navclient&aq=&oq=fire+lapping+an&ie=UTF-8&rlz=1T4ADFA_enUS508US508&q=fire+lapping+an+air+rifle&gs_l=hp..0.0i22i30l5.0.0.0.8225...........0.YN0SpWGKRTQ (https://www.google.com/search?sourceid=navclient&aq=&oq=fire+lapping+an&ie=UTF-8&rlz=1T4ADFA_enUS508US508&q=fire+lapping+an+air+rifle&gs_l=hp..0.0i22i30l5.0.0.0.8225...........0.YN0SpWGKRTQ)
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It certainly won't hurt to try fire lapping first. I like the idea of using a q-tip to carry the abrasive ahead of the pellet. This barrel may call for more drastic measures. I think that if I were to remove the defects I'll end up with a barrel that is too loose. The defects I can feel are not subtle. I wish I was beginning with a barrel that shot .75" groups. It's closer to 2" at 25 yards. It's a 1992 and who knows how the previous owners treated it.
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did u ever try jsb 10.3?
Josh
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did u ever try jsb 10.3?
I admit that I haven't. I have a pretty extensive pellet collection though and have always been able to get acceptable results with at least a couple of pellets I have on hand. Those are about the best groups I can achieve with CP 10.5. RWS pellets shoot about as well as my smooth bore Crosman 760 does with BBs.
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before going any further I would really suggest you try them. if I had any left id send you some but ive done away with .177.
Josh
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If you really want to do the crown, you don't need to cut any length. Carefully and slowly file the muzzle 'til you get past where the bore meets the muzzle. Then do the old brass screw trick to clean the edge.
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before going any further I would really suggest you try them. if I had any left id send you some but ive done away with .177.
Josh
Josh different pellets will not help a barrel that has problems...
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The problem is very evident when pushing a pellet through from the breech. It's snug, then loose, then a couple more snug spots, then it feels like the ridges of a washboard for the last half barrel to the choke. There is another slight loose spot just before the choke. Those grooves are not just at the crown. You can feel them for half the length of the barrel.
"
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really? I obviously know nothing about barrels and airguns. ::) please show me more of the quotes I have already read wise one.... but its worth a shot before going to extreme measures.
Josh
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really? I obviously know nothing about barrels and airguns. ::) please show me more of the quotes I have already read wise one.... but its worth a shot before going to extreme measures.
Josh
I guess maybe not as much as you think, I know I first started shooting over 40 years ago and am still willing to listen...
I would take the time to explain why that description I quoted tells that different pellets will not fix the problem but I obvious ruffled your feathers...
If you are willing please let me know how the JSBs will help... I just might learn something new...
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fair enough, back when I dabbled in airguns that typically came from the factory with "remarkable" barrels. I experimented and tried many things and many pellets. one bore was quite oversized and many pellets would fall into it a ways, one was tight at the muzzle end, another which ended up living on the rifle that I bought 4 barrels for had this issue of tight and loose spots in the bore. it shot nothing worth mentioning really. after various efforts of lapping back to health and yes lead slug in a .177 barrel is quite possible just a pita. well one last try was about all it took to push me over the edge. was ready to just have a lw machined to fit when someone suggested I try a jsb 10.3. never thought anything of it being more cylindrically shaped or longer than most other .177 nor did I think it would make any difference as I had various 10+gr pellets around. well I ordered some for @^52 and giggles. come to find out the gun ended up shooting 1/2-3/4in 5 shot groups at 50yds. maybe it was luck, maybe was the odd design of the pellet. so there is my reasoning. anything is worth a try and I had much rather buy a $14 tin of pellets and have a chance they may shoot well enough than to invest more time and money in a gun that's worth $250 at best.
Josh
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I had doubts if fire-lapping would help but I liked Kirby's idea of loading the abrasive on a q-tip. I used what I had on hand, automotive rubbing compound, the red paste. It did more to help accuracy than anything I've tried so far. I shot about 25 q-tips with a CP 10.5 behind it. It is looking like it wants to group. 5 shots out of 10 are touching. I'll lap it some more when I have time and try different pellets. This is encouraging! I'm going to try this on some other barrels.
Jon
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Thanks Josh I can see how the jsb and some longer pellets may help in some cases...
I was approaching it fron Fixxing the problem angle not hey this pellet just might smooth things out...
I think Jon should push a pellet thru from the muzzle side and see what the high & low spots feel like in comparison to the choke...
then start marking the spots running pellet thru from both directions until it is well marked and a very good feel and understanding of the tight spots is obtained
if it is more than .1"-.4" tight spots then a bore mop or tight patch(if smaller spot than the mop) with the bore paste and work that area by hand. tedious but cheating with very fine wet dry is a touch risky...
It all depends on what he feels when he pushes the pellet thru from the choked end how loose are the loose spots and how tight are the high spots...
so there is my reasoning. anything is worth a try and I had much rather buy a $14 tin of pellets and have a chance they may shoot well enough than to invest more time and money in a gun that's worth $250 at best.
Josh Tinkering is part of the attraction for some of us and we do not care for $
Sometimes we get to learn a new method or come up with one...
From having read some of Jon's posts I think he likes working on these things...
take a look at Jasons(nervous triggers 7 page journey about fix or just change a barrel In the end he gained a feel... and also had a(frustrating at times) journey at the same time...
Thanks again, I did fail to see it from the angle you did, it might even help this barrel, but shot to shot consistency might be bad enough to prevent it, imo.
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oops Jon posted while I was typing ( I am very slow)...
Jon take a little time to get to know your barrels first... I would say more but have to take my sons Manx to the vet ...
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It is easy to over do fire lapping deciding what you have and when to stop is the trick...
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It is easy to over do fire lapping deciding what you have and when to stop is the trick...
I understand. Too much of a good thing...
I had to try some boxed CPDL. All within .75" at 25 yards, most touching the same hole. Those high fliers in the previous target were loose fitting CPDH tin pellets. I'm beginning to feel like this barrel may have potential.
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It was suggested to me that rubbing compound is too soft and I should try something more abrasive. Trying to use only what I have on hand I used white Colgate toothpaste, followed by JB bore compound. After thoroughly cleaning barrel I got this 1/2" 6 shot group at 25 yards. This air rifle is beginning to behave like a Diana with five out of six touching and the ubiquitous flier. I won't have to replace the barrel after all! :D I think the stock deserves to be refinished. Yay!
Jon
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8) 8) 8)
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Glad to hear it's working better now Jon.