JSB 22 caliber 25.39 gr accuracy?

What speeds r u trying? 920-960 is the range I would try.

from what I gather the guy using them in BR spend considerable time sorting 

That doesn't sound right. Have a Prophet myself but don't shoot benchrest. Using JSB 25.39 redesigns and is very accurate. But every gun is a little different. The gun came to me shooting Monster redesigns at 125ish bar and 954 fps. tuned by the shop I purchased it from. At that setting hammer spring was set to use all the air in the charge. Had a lot of scope trouble and is currently set down to 125 bar and 890 fps (wanted shot count for a change) and still shoots lights out. My grandson just sat down and shot a 1 inch spin 72 times (or 6 magazines) at 30 yards and still left paint all around the edge 3/4 inch group (he could've had some clean misses but he's not talking, lol). Glad it made him happy and no idea he had been practicing.. Have heard of other tunes most revolve around 140-150 bar and like 930-940 fps and 960-985 fps but I haven't tried them. I use the prophet for varmints mostly and shot typical 15 to 55 yards. What speed you are 18.13.

I’m talking 100y benchrest… 

You've done an awful lot of adjusting with no results. One thing for sure I would do is remove moderator if any and test which you most likely have already done. If it still doesn't group, contact the shop you purchased it from for help. They should work with you. Another possibility would be try FX 25.4 pellets which are JSB's but first run of the die. Sometimes tightens groups up, for no apparent reason. Barrels can be a little picky. Hope you find the cure on this madding ordeal. Eric

I have a RTI Prophet performance with the 22lr barrel. I haven't used the JSB 25.4gr but I do shoot the FX 25.4gr... shoots great out to 100 and everything in between. Shoots 18gr out to 80 good but falls apart any further ( same tune as the 25.4gr) H&N 21gr shoot just as good as the FX 25.4gr also. might wanna check for clipping...torn o-rings on or in the barrel... 

jpgf sorry if this sounds dumb, but are you shooting off of a front bag only, or do you also use a tail bag? 
My RedWolf shoots the redesigned pellet very well out to 100 yards. But without the tail of the rifle anchored the groups aren’t nearly as good.

Edit: Like the guys said above, definitely shoot without the moderator, and at say 30 yards from a super steady rest to see if it’s clipping. That’s a fantastic rifle and you should be able to overcome the issue. Good luck!

I have the RTI Prophet .22 with the long range barrel. I’ve been shooting all three pellets mentioned at 50 yards benchrest (JSB 18.13, H&N 21, JSBMR 25.39). I’ve been getting consistent .35 to .45 inch groups with all 3 pellets. Currently, I’m shooting the 18.13s at 955fps. Hammer spring is backed out to about flush, reg is set about 98 - it’s amazing the power at this mild setting. It’s also amazing that it can shoot the 18.13s so accurately at that high speed. I have used my 50 yard zero at 65-70 yards d there is basically no drop with the 18.13s. I’ve got about 5 tins of 25.39s that I’m saving for a trip to my brothers where I can shoot out to 100 and beyond- I plan to do some 100 yard benchrest testing there - using Midas Tac 6x24 scope, so hopefully enough magnification. The tunes I’ve seen for the PP LR .22 guys shooting 100 yard competitions with the 25.39s seem to have the reg set very high 160-180 bar. They shoot the 25.39s at about 1050fps. This seems insane, but the gun seems to have been developed around that tune.

When I tested one of the first Performance LR models, it did not do well at the typical 970 area that we had been so successful with on the Daystates . Contacted the factory and they responded that it needs to be 1010 fps. We moved it up to that and suddenly, it started doing very well.

There is also a bit of inconsistency from batch to batch in both the 18.1s and the 25.4s. One batch is brilliant and the next is crap. It can be frustrating to try to discern if it's you, the rifle, or the ammo.

The Daystates are 1 in 17.7 twist LW polygonal and the PP LR is 1 in 30 LW polygonal. They will be slightly different in their response .

Just info I've gleaned so far.

Bob

Joe,

Are you using a Compact or full size LR? Two totally different barrels and twist rates. My LR shoots MRDs best at 965. These rifles also require a VERY FIRM hold for best accuracy, at least for me.

I say it's the pellets. JSBs I got 2-3 years ago shot great in my Crown. Sub-MOA at 100. Redesignes I got last year shot awfully! They changed the design again. Now they don't shoot for crap. They sort of group OK and then 2-3" flier pops up at 50 yards. Way worse at 100!

With my Wildcat MK3 sniper the JSB MRD (redesigned 25.39g) shots amazing @50 mts, very good acuracy, 960 fps

I’m set at 125 and flush with hammer spring screw; 970 range with the 18s. I’ve tried too many tunes to go through with the 25s, to the point where I wasn’t sure if there was something wrong with the rifle. I still am not totally confident that there isn’t however I’ve been getting fairly consistent 1/2” or less groups with the 18s in less than ideal conditions. 
I tried the above settings with the 25s and was in the 940 range but accuracy was in1” or more range. 
Trying to narrow “problem” and didn’t know if perhaps the 25s are just not inherently less accurate.

Oh, I do size the pellets to 5.52

Click to expand...

Yeah, with my RAW HM100x LRT, have tuned for FX 18.1, 125 bar set point and hammer spring backed off all the way. Shooting at 1050 fps which is too fast, but getting 7 or 8 of 12 shot clip in 1 MOA at 100 yards (no wind). Was going to ... and likely will re-tune for FX 25.4 RD, but current tune with hammer spring all the way in gives me about 905 fps with the FX 25.4 RDs; groups not as good as faster 18.1 pellets.

Before I go with the FX RD tune, will lower FX 18.1 tune to 900 - 950 fps to see if that improves things - also need to adjust harmonic tuner on barrel.

 

I've shot and sorted a lot of 25.4 grain RD Monsters for my Red Wolf HP and my Delta Wolf. In excess of 10,000. The quality is, for lack of a better word, poop. Out of a tin of 200 pellets I'm LUCKY if I get 100 that are shoot-able in competition. The FX branded RDMs seems to be a little better.

Lately, in a tin of 200 pellets, I've had head sizes from 5.48mm to 5.56mm and weights from 24.8 to 25.9 grains. Quality control seems non-existent. My Red Wolf HP likes them head size 5.53 and weights in the 25.4 to 25.6 range. When they're good, they can be amazing. But they'll eventually break your heart. Sorting like this MINIMIZES the chance of flyers, but doesn't eliminate them. 

Which is why this year I'm shooting .25 King Heavy... Let's go Brandon!!!

I was looking for heavies pellets in .22 but I could get the JSB MRD's only, with a new price about two weeks ago and I was shocked with the bill.

I am not considering the Leshiy2 as a target gun especially the trigger is not meant for that game, but this is what is left in .22 from my locker cleanup.

For several days I tried many things @ 50 meter rings, my 500mm R*ssian poly barrel just didn't like the new MRD's, the previous AA Field 15gr was grouping way way better in a perfect day but really vulnerable with a wind.

I re-crown the L2 500mm barrel last weekend, and only today the weather cooperated and I had finally some good time at my gun range.

I shot almost a hundred pellets again @ 50, I got a best grouping about a MOA with a speed 920ish. Looks like a new crown improved a lot, but still room to improve.

I have a plan for tomorrow (Saturday) to raise the speed to 950-960, let see how that works.

btw, I washed and lubed the JSB redesignes, I usually do ten tins once I start, but I had no time to sort them. This could explain for flyers, because I shoot from a heavy tripod and rear monopod, so the gun is almost like anchored to the bench.

Today at my gunrange, 50 meter target. I made roughly about 200 shots, front rest is a heavy tripod rear rest is a monopod.

Calm late spring weather not much air motion.

.22 JSB MRD 25.4gr, speed 957-960 fps, up from 920ish two days ago.

.22x500 mm poly barrel shooting w Leshiy2 which I am considering - not a competition level target setup. 8 shots mag.

I don't see any difference in average 1" group size from switching between two speeds, every second or third group had a flyer or two.

I have the same thing going on with my Prophet and MRD, don’t group at all compared to 18’s or NSA’s. I’ve tried from 900 to 970 and just crap. I do have some FX variants I’ll try, and may polish the barrel when I pull it out next. I’m gonna trust Centercut on this, and blame this run of monsters. I tried some HN 21 grain at dusk last night, and they show promise at 50 yds. I’ve grown bored with 50 yds, and have been trying 100 yds lately. Now That is a Challenge! I put lights on my target so I get a chance to shoot in low wind and loving it.