JP barrel/bolt rimfire kit not shooting well, ideas?

[ToddM]

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

 

[nesikabay]

Best advice I can give is sell it. Use the money to get a Vudoo. problem solved

 

[Hellbender]

Do the obvious, simple stuff first.
Put in a new FCG with a stonger hammer spring and try that. The vertical stringing suggests poor ignition.

 

[ToddM]

Yeah I'm going to try a couple different lowers one with a mil-spec trigger and the other with a Gieselle. I was looking at it today and there's only a tiny bit of the rear of the firing pin exposed at the rear of the bolt body, maybe 1/16" but it has to travel at least 1/4" into the bolt body to "bottom out". When the firing pin is bottomed out it does look like it should really be hitting the cases, much deeper than I've seen.

Cleaning it today I noticed that only the very bottom edge of the firing pin had any wear from the hammer. I wonder if the curved nature of the Hiperfire trigger is not squarely hitting the firing pin. That might seem to align with the inconsistant ignition and weak looking firing pin hits on the brass. Either way it's super easy to try a couple different lowers with different triggers to eliminate that possibility if nothing else.

 

[ToddM]

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 esp for the $.

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.

 

[Hellbender]

Do you have a muzzle brake on it? You can over torque a brake and it can ruin a bbl.... on a .22LR hand tight with blue locktite is plenty.
Just a brake in general is just adding a useless question mark on a .22LR. (except aesthetics, or if you are banging the gun around and need muzzle protection)
Look at your bbl. crown with a magnifying glass, any problems, however slight?
Suppressor...on and off?
A high quality AR22 (CLE, JP, etc) should put good ammo (it likes) into 1/2" or better at 50 yards.....IF....IF.. you can do your part.... AR's are hard to shoot really well, and a .22LR adds to the difficulty.

 

[nesikabay]

Vudoo Vudoo,

 

[ToddM]

It has a thread protector on it, one of the first things I tried was to spin it off to make sure it was not crushed on there, didn't matter. No supressor, no obvious crown damage. I don't see anything obviously horrible with a bore scope, but that said I have a Clark S&W 41 barrel that looks so bad inside most would refuse to shoot it and it's test target with Eley Match is multiple groups 1/2" at 50 yards out of a rest. So I really don't feel that even if I saw something "odd" in the barrel it would really mean it's "bad".

I really doubt it's my shooting ability, the same day with the same rest setup and scope model, my 6.5 AR was shooting 3/4" at 100. The 10/22 while not an AR is also a semi-auto and probably suffers from some of extra stuff going on as far as being more critical of follow through while cycling and it was shooting fine.

As to the Vudoo, I already have a couple bolt 22's that shoot great, wanted to do an AR for giggles.

 

[Kisssofdeath]

Well, an't nothing like doing it for giggles.

 

[hlee]

Run a few patches through the barrel. Shoot 20 of "the good stuff" into the dirt. Then shoot 5 for record. A $10-12 box of fifty is nothing compared to what you spent on that JP setup. My experience has been that anything you can get at a big box store is just good enough to be functional. Shoot the Lapua and Eley if you want to see the edge of performance in your rifle.

Saying your 22lr ain't a shooter because it doesn't shoot CCI into 1/2" is like saying your AR15 ain't a shooter because it is 2 moa with m855.

 

[ToddM]

You might want to read the whole thread. I shot Lapua, 3 types of Eley, CCI Std, Wolf Match, Automatch, SK Rifle, Fiocchi Exacta, and as you said the first 38 of each box went "into the dirt" before recording two 5 shot groups. None of those shot better than 1.25" on average, I really doubt I'm going to find some other "magic" bullet that puts into the 1/2" range.

 

[ToddM]

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.