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-   -   JP rimfire barrel/bolt kit not shooting well, ideas? (https://www.rimfirecentral.com/forums/showthread.php?t=1171087)

toddm 09-06-2019 06:27 PM

JP rimfire barrel/bolt kit not shooting well, ideas?
 
So I put together a JP rimfire kit into an Aero upper and lower, Magpul PRS, with a Hiperfire trigger, black dog mags, seekins handguard, and a known repeatable 25x optic/mount, shooting off a front rest and rear bag. I've built a few .223/6.5 AR's and never really had any problems. I've probably put 200-300 rounds through it.

I've had no functional problems, however the accuracy has been pretty abysmal. I'd say 1-1.5" at 50 yards, 5 shot groups (all the range will allow loaded at once) Federal automatch is probably over 1.5", wolf match, CCI Standard, Federal gold medal are slightly better, best group on the day might have been 3/4". Didn't seem worth wasting Eley Match, Lupua or anything I have that's more expensive if it wouldn't group better with CCI standard, Wolf, or Fed gold medal. I've tried it with and without the threaded barrel protector, accu-wedge, trying to free recoil it and hold it tighter into a relaxed shoulder as I would a centerfire, doesn't seem to make much difference. As a reference my Volquartsen 10/22 is shooting in the 3/8-1/2" groups with CCI standard and Wolf.

I've noticed 2 things but am not sure of the cause.

1) I collected some brass, and while I've had no mis/non fires or rounds that felt/sounded weak/delayed, the firing pin hits on the brass seem very light compared to my other 22's across the various brands of ammo I've tried. Not sure if this might be related to the hiperfire trigger, so I may swap that out.

2) The groups appear to have more vertical stringing to them than horizontal, but it tosses a lot of flyers and it doesn't appear to be the first hand chambered round. Perhaps this is related to #1 if I'm getting poor firing pin hits and weak/variable ignition, but I'm just spitballing.

I can and may put it in a new upper I have a Mega extra thick upper I could try.

Just thought I'd poll other people have seen through their experience that might be causing it, not blaming the JP setup because they have always been top notch quality and I've seen a few of their JP 22 kits shoot pretty amazing.

Thanks,

Todd

octanejunkie 09-06-2019 06:34 PM

Shoot it off a rest or bags for best accuracy

How tight is the barrel nut?

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zukiphile 09-06-2019 09:20 PM

I've never had a JPE, so discount my ideas as appropriate.

Quote:

Originally Posted by toddm (Post 11599053)
a Hiperfire trigger,...

1) I collected some brass, and while I've had no mis/non fires or rounds that felt/sounded weak/delayed, the firing pin hits on the brass seem very light compared to my other 22's across the various brands of ammo I've tried. Not sure if this might be related to the hiperfire trigger, so I may swap that out.

If you have the toggle springs installed, you should be getting ridiculously hard hits. Maybe you are getting very firm hammer fall, but the FP stop just doesn't allow deep hits.

I use a light hammer spring on a Geissele and that doesn't seem to have caused any accuracy problems.

Quote:

Originally Posted by toddm (Post 11599053)
I've had no functional problems, however the accuracy has been pretty abysmal. I'd say 1-1.5" at 50 yards, 5 shot groups (all the range will allow loaded at once) Federal automatch is probably over 1.5", wolf match, CCI Standard, Federal gold medal are slightly better, best group on the day might have been 3/4". Didn't seem worth wasting Eley Match, Lupua or anything I have that's more expensive if it wouldn't group better with CCI standard, Wolf, or Fed gold medal.

I don't think that's how ammunition selection works. I'd test everything I had. I've had some pleasant surprises running something I was sure would be disappointing only to find that it was what the barrel preferred.

I don't blame you for being disappointed, but I would put at least 500 rounds through it before I were certain that the rifle had a long term problem. I have had 10/22s that need to settle after being assembled and improve over the first 1000 rounds dramatically. I thought ARs were immune to that, but maybe they aren't.

toddm 09-06-2019 09:33 PM

Quote:

Originally Posted by octanejunkie (Post 11599061)
Shoot it off a rest or bags for best accuracy

How tight is the barrel nut?

Sent from my Pixel XL using Tapatalk

Rest setup should be good, it works for 1/2 groups at 100 from my Bartlein barreled 6.5 AR10.

Barrel nut was torqued to 45 ft/lbs which is normally where I start, and it was done repeatedly to season the threads.

toddm 09-06-2019 09:42 PM

Quote:

Originally Posted by zukiphile (Post 11599199)
I've never had a JPE, so discount my ideas as appropriate.



If you have the toggle springs installed, you should be getting ridiculously hard hits. Maybe you are getting very firm hammer fall, but the FP stop just doesn't allow deep hits.

I use a light hammer spring on a Geissele and that doesn't seem to have caused any accuracy problems.



I don't think that's how ammunition selection works. I'd test everything I had. I've had some pleasant surprises running something I was sure would be disappointing only to find that it was what the barrel preferred.

I don't blame you for being disappointed, but I would put at least 500 rounds through it before I were certain that the rifle had a long term problem. I have had 10/22s that need to settle after being assembled and improve over the first 1000 rounds dramatically. I thought ARs were immune to that, but maybe they aren't.

Yeah I figured if anything the Hiperfire would really hit the firing pin hard, but perhaps it's as you said the stop is not letting it go any further. I can say of all my 22's it's by far the lightest hitting firing pin, I collected 10-20 of them and I'm actually surprised some even went off it hit so light. Tried 2 sets of springs in it, didn't seem to make a difference.

I can try other ammo, I know they can vary in what they prefer, but to be honest I've never had a .22 that ever turned out to be a good shooter that would not shoot one of those I tried better than 1-1.5" and then magically jumped down to 3/8-1/2" with another brand, especially with Wolf.

zukiphile 09-06-2019 10:03 PM

Quote:

Originally Posted by toddm (Post 11599235)
Yeah I figured if anything the Hiperfire would really hit the firing pin hard, but perhaps it's as you said the stop is not letting it go any further. I can say of all my 22's it's by far the lightest hitting firing pin, I collected 10-20 of them and I'm actually surprised some even went off it hit so light. Tried 2 sets of springs in it, didn't seem to make a difference.

I had a Larue set up with a bunch of Taccom shims so that even that beast of a hammer would only make a light impression. It always lit them, and I though I was doing my FP a favor.

Quote:

Originally Posted by toddm (Post 11599235)
I can try other ammo, I know they can vary in what they prefer, but to be honest I've never had a .22 that ever turned out to be a good shooter that would not shoot one of those I tried better than 1-1.5" and then magically jumped down to 3/8-1/2" with another brand, especially with Wolf.

I sat on a few thousand rounds of Federal 711b for a couple of decades. Every new rifle saw some of it, and none ever shot it well. It's obviously terrible ammunition. Then I bought a Lothar Walther barrel. At 50 yardst shot CCI SV and RWS SSHP to an inch yards - pretty disappointing. At the next session, I tried some Automatch and got just over a half inch, so I pulled out the garbage 711b. It did better, and not just a little better.

I know other peoples' anecdotes have limited value to you, but you seem pretty early in the process. On the other hand, for the price of that JPE kit, you should reasonably expect to be posting about how great your new rifle is.

toddm 09-06-2019 10:27 PM

Not at all, if others have had the experience where "problem child" barrels that shoot 1-1.5" with match ammo and then drop way down to 3/8-1/2" groups with other brands I'm happy to keep trying various stuff I have to see if something "clicks". My knee jerk reaction was after shooting ammo my other 22's may not shoot their best groups with, but one has always performs pretty well, that shooting $15/box lapua or Eley through it was just throwing $ away.

I'll probably drop JP a note as well see if they have any suggestions on what ammo to try, or if the light firing pin strikes are normal.

octanejunkie 09-06-2019 11:34 PM

Barrels definitely break-in over time, shooting it often helps. You may not see it's full potential for a few hundred rounds.

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zukiphile 09-07-2019 07:21 AM

Quote:

Originally Posted by toddm (Post 11599293)
Not at all, if others have had the experience where "problem child" barrels that shoot 1-1.5" with match ammo and then drop way down to 3/8-1/2" groups with other brands I'm happy to keep trying various stuff I have to see if something "clicks". My knee jerk reaction was after shooting ammo my other 22's may not shoot their best groups with, but one has always performs pretty well, that shooting $15/box lapua or Eley through it was just throwing $ away.

I'll probably drop JP a note as well see if they have any suggestions on what ammo to try, or if the light firing pin strikes are normal.

I won't tell you what to do, but what I would do:

I'd finish a box of automatch, cleaning it every 50 or 100 rounds. Then I'd take the JPE and Volquartsen and shoot them side by side with the same ammunition on the same target and label the target.

When contacting JPE, provide the image of that target. You obviously know how to shoot a group, and it isn't as if you are shooting stuff from a bulk box you bought from an end of aisle display at the Mart.

If you've ruled out you and the ammunition as the problem, you are likely to get more coherent help from JPE.

octanejunkie 09-07-2019 07:34 AM

JP doesn't seem to readily publish the twist of the barrel in their rimfire kit that I could easily find on their website, but I found this thread
https://www.ar15.com/forums/ar-15/my...kit/15-731345/
Zuk was there[emoji4]

Seems it is possible to wring decent accuracy out of that kit

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toddm 09-07-2019 03:15 PM

I do want to try a different trigger. The firing pin for the JP bolt only sticks out a tiny bit from the back of the bolt 1/16" maybe, and it does have a firing pin spring holding it rearward. So it probably relies on the hammer hitting it perfectly square and inertia driving it forward (if you flush the firing pin with the bolt body the pin has not extended from the bolt face yet. Pushing the firing pin till it "bottoms out" is probably the rear of the firing pin where the hammer strikes at least 1/4" or more recessed into the bolt body.

When I was cleaning it today and looking over the parts once thing I noticed is that the only wear on the back of the firing pin where the hammer should be hitting it is at the very bottom edge, and the Hiperfire has the top 1/3 or so of the hammer rounded back. I wonder if it's not hitting the firing pin square. Easy enough to swap out a mil spec trigger to see, I can also throw it on another lower with a Gieselle.

I can throw a few more brands of ammo at it as well.

ivan 09-09-2019 08:37 AM

Quote:

Originally Posted by toddm (Post 11599945)
I do want to try a different trigger. The firing pin for the JP bolt only sticks out a tiny bit from the back of the bolt 1/16" maybe, and it does have a firing pin spring holding it rearward. So it probably relies on the hammer hitting it perfectly square and inertia driving it forward (if you flush the firing pin with the bolt body the pin has not extended from the bolt face yet. Pushing the firing pin till it "bottoms out" is probably the rear of the firing pin where the hammer strikes at least 1/4" or more recessed into the bolt body.

When I was cleaning it today and looking over the parts once thing I noticed is that the only wear on the back of the firing pin where the hammer should be hitting it is at the very bottom edge, and the Hiperfire has the top 1/3 or so of the hammer rounded back. I wonder if it's not hitting the firing pin square. Easy enough to swap out a mil spec trigger to see, I can also throw it on another lower with a Gieselle.

I can throw a few more brands of ammo at it as well.

If that is the case that is gonna suck for me - I got a Hiperfire 24E when they were on sale for half price closeout to eventually be used in a accurate dedicated 22 upper... and JP was on my short list.

Please let us know how it all washes out....

toddm 09-09-2019 06:24 PM

Yep, same here this is one of two Hiperfire 24 3G triggers I got when they were blowing them out as well.

toddm 09-14-2019 08:34 AM

Well I've done two more range sessions, and on the good and bad side the Trigger is not to blame.

I've tried two lowers, 3 triggers, and even put the barrel into another upper Mega slabside, that I know performs. I swapped the scope/mount over to my 10/22 Volquartsen and it had no problems shooting 1/2-5/8" groups at 50 yards and 1-1.25" groups at 100 with Wolf, CCI was a little worse, Eley/Midas/SK a touch better, and that's without throwing the first hand loaded round into the dirt. Not surprising my volquartsen has always seemed to shoot wolf very well.

Today I shot Wolf, SK Rifle, CCI Standard, Remington Eley Club, Remington Eley Match, Eley Match, Lapua Midas, Fiocchi Exacta, and Automatch. My process was to shoot 38 rounds when swapping ammo, and the last 10 for "official" score (range only allows 6 rounds loaded at a time and I put the first one hand chambered into the dirt).

I had two groups that were in the 5/8-3/4" range (interestingly they were both with different ammo and the first groups out of the barrel after changing ammo but then they spread way out), most were in the 1.25-1.5" range. Still seemed to be more vertical than horizontal stringing.

I'll get ahold of JP and see what they say, at this point I don't think there's a whole lot more I can try on my end.

toddm 09-20-2019 02:54 PM

1 Attachment(s)
I just realized I never put any group pics in. Still need to get ahold of JP next week.

To be fair to both rifle's groups this day had some 10-12 mph tunneling breeze, and the range i shoot at uses a conveyor belt like material for target mounting so they swing a bit in the breeze, I'd say this day to about the first outer ring or about 1" so timing shots with the wind gods was critical. Volquartsen on the left (wasn't even tossing the first round into the dirt) and JP on the right. All 5 round groups. Ones circled on the left target were my fault where the gun had more movement than normal under recoil/follow through.

The one good group with the JP is odd, but I've seen it 3-4 times now where all the stars will align and it would stack 5 in a row across different ammo. However I can have a shot with the JP feel great, normal reticle movement in follow through, shots feel identical, one will be in the center and the other will be 1.5-2" out. I also noticed shooting at 100 with the JP, it looked like a couple of them might have been starting to tumble, they didn't look like clean holes. Groups at 100 were in the 4-5" range, but I only tried Eley Match at that range as I had a few left over.


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