BSA R10 Accuracy Issues

[robertr]

Might not help at all but here is a pic of my Scorpion Barrel, still dirty but gives you something to compare to. Can take a pic after a cleaning too if you like, I was going to clean it anyway.
I thought that was a better pic that that, I will try to get you a better one in the daylight.
Edit; It's a bit better now.

[Nitrocrushr]

400 Clover, Tight patches on a round jag tip/hard rod and give it a good burnishing job.
Too bad your across the country ... barrel in hand a 20- 30 min process

Thanks Scott, I might get some Clover 400 and polish that last 1/4-1/2" of the bore.  Those tooling marks must be snagging lead and causing the end of barrel fouling.

Yes, the crown is recessed but squared off with no taper.

I get my tank filled at a local dive shop.  They claim their air is very dry and breathable.

robertr - Thanks for the picture.  Your rifling is completely defined at the end.  On mine, it looked almost like a smooth bore in the last 1/4"

Steve

[solder]

Check out this video on barrel lapping.
Part1 

It gets a bit erotic near the end if you read the subtitles!

[DrPutz]

I had a similar "problem" with my .177 BSA R10.  It would not shoot JSB 7.9 or 8.4 grain pellets to save it's life.  I added a HuMa regulator and still no luck with them - I was in the 15 to 16 FPE with them.  I happened on a few AA 10.3 pellets and wow what a difference.  I was able to easily shoot sub MOA accuracy at 55 yards on the Hunter FT mode - I bought a dozen tins to have them available.  It almost became boring - that and I would grow tired after shooting roughly 80 to 90 shots in one session without a refill.  Anyway, the stock was not the best setup for Unlimited FT/WFTF, so I sold it recently and tuned it for higher FPE for the new buyer - around 22 to 25 FPE.  I could not test the accuracy in NE Ohio, but when the buyer got it, he reported that it shot like a shotgun with AA 10.3's.  He turned it back down to 900 fps or just below and the accuracy returned.  At the same time, I purchased a nice Gamo Dynamax (aka BSA Sprotsman HV) in .22 for hunting - no bells and whistles on this guy.  I tuned it as high as I could go while still getting 25 good shots within 4% ES.  I was able to achieve 3/4" grouping at 55 yards, while the weather was cooperating over the weekend with JSB 18's.  I brought it inside to practice in my 10-yard range in the cellar and tried the JSB 15.9's - a bunch left over from my previous .22 springer.  Anyway, I could not get any type of grouping even at 10 yards - pellets were wondering up to about 1-inch.  Based on this and other reports online, I suspect that the BSA barrels do not like high speeds.  Maybe this has something to do with their twist rate or maybe just the pellet-barrel-velocity magic formula.

So, long story short - maybe it is going too fast for the BSA barrel.  Try either turning the speed down or upping the pellet to JSB 18's.  Worth a shot before more lapping of the barrel.

Dan

[Dairyboy]

Lol I was shooting the 8.44 gr JSB and Polymags at 1000fps as it came from the box and they shot very very accurately single hole at 25yds never tried out farther but I did end up turning it down to 890 with 10.3 and still shot great so idk if it's the speed exactly. That's a bummer though as I loved my BSA R10 real accurate and sweet shooter

[solder]

I agree. Finding the right velocity/pellet/distance combo can make a huge difference. 10.65 H&N work pretty good for me. I gotta get me some AA10.3 and give 'em a try.

[Nitrocrushr]

Thanks for the feedback guys.  Shooting off the knee of the velocity curve I can get velocities from 860-905 (15.89 gr) using Huma regulator settings of 130-140 BAR. I've tested JSB 15.89, 18.1 grain and AA 16 grain pellets.  I was at 139 BAR and 897 fps with the 15.89's when I finally realized the choke was fouled.  That is where the rifle is set right now.  During the testing when I was trying to drill down on the accuracy problems, I had tested from 130-140.  Even with the fouling, the groups seemed to be tightest in the 890 fps range.  At this point I have no option but to scrub that fouling out and while I am at it, I will polish that bore to get the tooling marks out of the choke.  I'll get that complete this weekend and back to the range for more testing.  If this fails, I will experiment with lower velocities (although I do think the fouling began at lower velocities and continued to worsen the more I shot).  If all else fails, I will get a new barrel.  John Knibbs has them in stock for under $100.  I'll know if the bore scrub and polishing helped by Sunday night.  If it works I'll be good to go   If not, a new barrel will be on the way.  I will send pictures of the tool marking in my bore and request that they inspect the new barrel before sending

Steve

[DrPutz]

Here's a couple of groups from tonight from my Dynamax .22 - I was lucky enough to have warmer and calm weather to get some longer range targets in.  These are 55 yards in the dark with HFT mode - bucket and sticks, bore has not been cleaned in 100+ shots or so after tuning.   With my rubber band tune, the 15.9's are going 880 fps, while the H&N extremes were going 820 fps, unfortunately I have not chrony'd the JSB 18's yet

The first one at the top is 10 shots with JSB 18's (target #2, targets are 1.25" at widest), a bit of left to right wiggle on my sticks is pretty evident in the nickle size group.  The second one shows a great 5 shot group at the top with JSB 18, then a couple of 1" to 2" open groups with JSB 15.9.  I also tried H&N Barracuda Hunter, which was open, but to that was to be expected.  Then a final 5-shot group on #28 at the bottom - the one shot to the right was just after the H&N Hunters.  I always find that when switching pellets, there is a couple of shot lag before the grouping returns.  Point being - the JSB 18's seem to work well while the 15.9's do not - I am attributing that to speed, but there could be other issues at foot here.  I could see a bit of a spiral in the 15.9's , since I was shooting under lights.  Good luck with your barrel work.

[Taso1000]

Hi All,

Worst case, could the damaged rifling be cut out of the bore with a lathe leaving the length and threads of the barrel alone?  So the good rifling would end 1/4 before the crown?

Thanks,

Taso

[rkr]

Hi All,

Worst case, could the damaged rifling be cut out of the bore with a lathe leaving the length and threads of the barrel alone?  So the good rifling would end 1/4 before the crown?

Thanks,

Taso

The barrel might be a bit loose after that, although the "choke" (BSA says tapered barrel from hammer forging) is typically around 1" long.

[solder]

Hopefully a definitive cause and resolution will be found and we will all learn something.

[nervoustrigger]

Here's a couple of groups from tonight from my Dynamax .22 - I was lucky enough to have warmer and calm weather to get some longer range targets in.  These are 55 yards in the dark with HFT mode - bucket and sticks,

...

the JSB 18's seem to work well while the 15.9's do not - I am attributing that to speed, but there could be other issues at foot here.  I could see a bit of a spiral in the 15.9's , since I was shooting under lights.

That's really good shooting at 55 yards from a bucket and sticks, particularly being a 10-shot group.  I'm not surprised the JSB 18.1 are shooting well but it's interesting that you're picking up spiraling with the 15.9.  880fps is not too fast.   My experience has been that a rifle which shoot the 18.1 well will often shoot the 15.9 well.  But if not, they at least didn't spiral.  I shoot a good bit at night with the aid of a strong flashlight shining downrange so it's easy to follow the flight path.  I guess it doesn't matter...use what works

Again, good shooting!

[DrPutz]

I have never had good luck with the JSB 15.9/AA16/FX16's - I have several tins and I wind up using quite a few for chrony.  It does remind me that I should order more 18's since I am down to my last tin.  I have some lighter pellets to try when it warms up over the weekend.  Just a reminder that the gun picks the pellets and you have to try a few before the right combination is found.  I am interested to see how the barrel cleaning and polish help.  I have to try the same on a Marauder .177 that shotgun patterns.

[Nitrocrushr]

I have never had good luck with the JSB 15.9/AA16/FX16's - I have several tins and I wind up using quite a few for chrony.  It does remind me that I should order more 18's since I am down to my last tin.  I have some lighter pellets to try when it warms up over the weekend.  Just a reminder that the gun picks the pellets and you have to try a few before the right combination is found.  I am interested to see how the barrel cleaning and polish help.  I have to try the same on a Marauder .177 that shotgun patterns.

Yeah I can't wait to get back in the shop this weekend and tear into it.  I'll be in the shop fresh cup of coffee in hand shortly after daybreak on Saturday morning The brief moments where I was able to get a peak in the box at the accuracy potential of this rifle, I liked what I saw.  Absolute single hole at 30 yards and 1/4"-3/8" ctc at 50 appear to be achievable....we'll see

By the way NICE shooting!!!  I hope to have a better accuracy report late Saturday or Sunday

[robertr]

A pic of one of my 50 y groups before snow fell and I went into semi-hibernation, 1/4" at 50 is definately achievable .

[Nitrocrushr]

A pic of one of my 50 y groups before snow fell and I went into semi-hibernation, 1/4" at 50 is definately achievable .

Nice group!! That's encouraging

[Hobbyman2007]

A pic of one of my 50 y groups before snow fell and I went into semi-hibernation, 1/4" at 50 is definately achievable .

Not to get off track but I'd like to know where Robert got his hands on the R10 in Canada . I'd love to get one but can't find one here .

[robertr]

 I Have the Scorpion SE which is more or less the same breach and barrel, R-10 has the bottle, installed reg and the match trigger. AirgunSource had a R-10 which I almost bought but went for the cheaper Scorpion SE instead.

[rkr]

I Have the Scorpion SE which is more or less the same breach and barrel, R-10 has the bottle, installed reg and the match trigger. AirgunSource had a R-10 which I almost bought but went for the cheaper Scorpion SE instead.

The trigger unit is the same in Scorpion and R10, adjustable blade position is the difference.

[Nitrocrushr]

Well I tore into the rifle first thing this morning and and pleased to say that I found something that could be contributing to some of my problems.  The outer layer of chrome on the pellet probe was flaking off.  There were literally hundreds of flakes of chrome all over the probe, and inside the ports at the end of the probe.  Inserting a Q-tip into the bore pulled out tiny chrome shavings as well.

I took a scotch brite pad and thoroughly scrubbed the pellet probe until no more chrome was coming off.  I even scrubbed inside the port at the end of the probe.  This was followed by a polishing with 1200 grit wet/dry.  At this point it appears as if it was the outer layer of chrome that did not bond to the layer beneath it.  I can see no signs of any more chrome wanting to lift off and the probe looks good.  I also had to flush all the chrome shavings from inside the probe guides.  WHile I was at it, I polished the inner surface of the metal guide in an effort to smooth out the bolt action.  Seems like it will be glassy smooth now

Well, time to get back to work, bore has been soaking with WD40, time to scrub the lead fouling out of the choke and give it a polishing with Clover 400

Steve

You can see the ring of fouling right inside the edge of the crown.  The Q-tip test did not show any signs of burs on the inside edge.  Nice and smooth, but as I said, chrome shavings were stuck to the Q-tip when I pulled it out.  It wasn't lead, it was mirror shiny chrome plating flakes.



All this just to remove 2 little grub screws to get the barrel off



Inside the probe port you can see one of the many hundreds of chrome flakes.  The entire probe and inner probe guide looked like a chrome plated porcupine.



Scrubbing/polishing out the port with scotch brite.  This was done to the entire bolt probe.  Spent about 30 minutes scrubbing the outer layer of chrome off, then polished with 1200 grit wet/dry.  Remaining layers of chrome appear to be solidly adhered



Polishing inside of the metal bolt probe guide - smooth as glass now



Completed bolt assembly