Sudden & severe accuracy degradation

[Moorlander]

On 9/1/2018 at 9:08 AM, bradders said:

Correct, although I will add that match grade bullets will always shoot better than open base FMJ types, you do need good quality heavy bullets to get the best out of your rifle at the longer distances and some of my best performances with .223 from 600-1000yds have always been shot with 80gn JLk VLDs

What twist barrel are you using with  80gn JLk VLDs ?

[bradders]

17 minutes ago, Moorlander said:

What twist barrel are you using with  80gn JLk VLDs ?

1:8"

[clover]

Thanks guys - some interesting discussion going on

On 9/1/2018 at 11:50 AM, Brummy Mark said:

I have very accurate .223, Lilja 1:6 twist barrel at 22" and have never tried 69gr, nor did I ever bother to try the 90gr vld which its throated for, I have 60gr Berger match varmints (h335) for foxing and 75gr Amax (N140) for longer range ie out to 1100yds, both rounds/loads shoot 1/4 moa at 100.

With 75gr shooting steel in mountain locations with extremely varied topography I have no issues at 600 to 850, after that the wind can play havoc with drop and windage, especially shooting across undulating terrain, with spurs and re-entrants several metres high/deep etc but with .308 running rounds with a very close BC, the same thing can also happen. But for that to happen across the flat gallery range, something is not quiet right, Im sure a logical investigation, starting with, as you have done, looking at things that can become loose, scopes that are defective and also adding in shooter errors.

All the best, as there is nothing more challenging mentally, than not learning why you missed the target. Until you have nailed the problem, learning can't take place.

Thanks for your support!

Sounds like you have a very nice setup and are getting cracking results considering you're not using the heaviest bullets on offer. I'd be very tempted to stick so 90gns though it though since you've certainly got the twist for it!

I can imagine how difficult shooting over the terrain you describe could be; but as you suggest my gut tells me something's amiss to cause my issues. Everything's tight as far as I can see through so it looks like an issue with the ammo, barrel, scope or driver! 

On 9/1/2018 at 7:46 PM, VarmLR said:

Yes.  People often beat themselves up about group sizes and chase tiny ES figures getting really anal about reloading, paying scant attention to bullet choice.  It's not just important, it's critical, especially where shooting in competition, to pick the right bullet.

We were shooting 600m today and several were using 20 inch .223's with 77gr smks.  No shortage of Vee bulls.  Light winds helped, but so did using the right twist with 77gr smks driven reasonably hard which was all that was needed to place a good percentage in the "4" ring.  By contrast, those of us using 6.5s were landing about the same proportion in the veebull( and that is exactly what should be expected from 6.5s!).  223 is more than capable at 600yds...it's pushing out much beyond that where it can get very sketchy, very quickly, with slower twist rifles and lighter, shorter bullets, especially when wind is thrown into the equation.

As Mark says above, at 600, on a reasonable day on a flat range, to scatter 223's across the target would suggest that something, somewhere, is not right.  I would argue that perhaps the 69smk is not ideal at that range...the 77gr HPBT being by far the better choice.  I would suggest that rather than a kit issue it could perhaps be a combination bullet and trigger technique where the spotlight should fall.  As an example, when dropping a large proportion of 6.5s into the centre, I wondered what effects at that range that slight trigger technique changes would make. I deliberately altered my trigger pull a little, and reckon that whilst still concentrating on the sight picture, breathing and body position, by adapting a technique change such as gripping a little firmer with the thumb on the grip or pulling the trigger with a slightly fuller reach, in both cases it opened up groups from around 4 or 5 inches to around 8 (ie from centre ring to 4 ring).  It also pulled them off a little to one side.  That was deliberate but still trying to keep things steady.  Don't under estimate the importance of both bullet choice and technique...both play a huge part in consistency and precision.

That's encouraging, thanks! As above I'm currently restricted to factory ammo so the 69gns are as good as it gets for now. I'm not an inexperienced shooter and after some fettling the trigger is breaking at a nice crisp 1.6lb and it's easy to squeeze with a relatively stable sight picture, so I don't think trigger technique is an issue.

I'd not rule out driver error completely as this was all at the end of a very long day plus I have little experience in shooting prone and do find consistent butt/shoulder positioning difficult. That said I'd have to be doing something pretty bad to sling them 2 mils from the middle - I can shoot considerably better than that freestanding!

Hopefully I'll get the chance to test it soon. Will give it a thorough clean before I do and start from square one again.

[clover]

An update. Got the chance to test the rifle again at 100, 200 and 300yd. The barrel was well-cleaned beforehand with copper solvent, 10 one-way passes of a PB brush, more solvent on a patch, dry patches until they came out dry, an oiled patch then a dry one to finish. All groups were shot from prone with a rear bag. There was a bit of a breeze but nowt too bad.

Results started off promising and went downhill..

100yd
1. 4 shot group: 3 shots into 12mm c-c (sub-0.5MOA); spoiled by a flier (2nd shot of the four) at 7 O'clock bringing the group size up to around 37mm c-c (1.5MOA).
2. 3 shot group: 3 shots into 13.5mm c-c (c. 0.5MOA). Bottom two shots through same hole. Group dispersion diagonally strung high-right to low-left. POI maybe 12mm lower than best three shots of previous group.

Making a composite of the two groups above would give a diagonally-strung group high-right to low-left of 37mm c-c - i.e. the 2nd groups would fit neatly in the space between the 1st group's main three shots and "flier".

200yd
1. 5 shot group: 4 shots of fairly even dispersion into 37mm (sub 0.75MOA) spoiled by a flier at 4 O'clock bringing group size up to around 88mm c-c (1.75MOA).
2. 5 shot group: 5 shots diagonally strung high-left to low-right, 69mm c-c (1.4MOA). Approximately same POI as previous group.

300yd
1. 5 shot group: 3 horizonally central, vertically strung into 84mm c-c (1.2MOA) further two shots at 3 and 9 O'clock bringing group size up to 162mm c-c (>2MOA).

 

So, it's not very clever. I can't see any trends in the groups other than they're pretty much all over the place - some otherwise acceptable (or in the case of those at 100yd very good) but with fliers; some evenly distributed, some strung in opposite directions. There appeared to be some POI shift between the two groups at 100yd; this could have been the clean barrel fouling or just the result of random distribution over two groups, within one poor group.

Group size increase with range is perhaps non-linear; possibly suggesting a stability issue but there are no keyholed shots, nor were there any at 600yd.. while this barrel should easily stabilise these bullets.

I'd like to think it's not the scope but haven't really ruled it out. I do have another I could try but am loathe to upset the mounts - thanks to getting screwed on my original choice of scope I do have a couple of pairs of spare rings, so I could get another set of bases to avoid disturbing the original setup.. on the one hand I don't want to chuck another £60 away; on the other I was considering hoovering up another set of stainless bases before everywhere runs out so I can build another set for another rifle in future using the rings I have. 

Ammo is another possibility - I've found very few reviews of the HPS Target Master I'm using, although it seems to use reasonable quality components (69gn SMKs and PPU cases). Out of curiousity I did weight the most recently fired 25 cases which came in with an extreme spread of 2.3gn / 2.3% of mean and std. dev of 0.68gn / 0.7%, which I didn't think was too bad compared to these values on 6mmBR.

When first testing the rifle I did run the first shots through it past the chrono - giving not too wonderful numbers - over 12 shots a mean of 2753ft/s, an extreme spread of 93ft/s or 3% and a standard deviation of 27ft/s or 1%. This was when the barrel was running in though, so might be an unfair representation of what the kit's capable of.

I did also notice that the meplats of some of the SMKs are fairly roughly formed and sometimes somewhat angled; while this can't do accuracy any favours I've seen similar on promo images for the bullets so I'm guessing it's not a handling issue and considered acceptable by QC. Despite this there are many accounts of these bullets performing very well, so I'm hesitant to blame them.

I'd like to test some more ammo but off the shelf I think I'm limited to GGG 69gn and PPU 75gn if I want heavier stuff. Does anyone have any experience of either of these rounds, or the HPS stuff I'm currently using for that matter?

Finally there's always me. Position was stable and i was able to hold the crosshairs within 0.5MOA with ease. Trigger control was generally good, recoil control less-so as it's not a position I'm used to and found the butt sitting in different parts of my shoulder - sometimes giving a lot of support against a bony bit; sometimes in the sofer "pocket" inside my shoulder. The 2nd 200yd group was shot with the gun tucked into the soft bit, purposefully maintaining head and shoulder position with respect to the gun during reloading, but still the group was less than great.

So there we go - tending towards subbing in another scope just to rule that out while looking to source some different ammo to try. As usual I'm always interested to hear any thoughts anyone might have

 

[VarmLR]

Quite simply, it could well be that the load doesn't suit your rifle as I'm assuming that Matt can't really load develop for customers due to practicalities.  There is one other trick left to try.  Find out who shoots this bullet with your barrel length and twist and find what load they developed for it.  Then ask Matt to try the same providing it is within safe parameters.  The bullet is very jump tolerant so keeping it to mag length will be fine.  FWIW my accuracy load is 24.6gr RS50 and the same for N140 both seated to mag length for a 26 inch 1/8 twist 223..

Other than that, try other factory loads at 200 and 300 yds.  If you get one that out performs the one you have then it rules out kit issues and confirms load issues.

[clover]

On 9/6/2018 at 7:13 AM, VarmLR said:

Quite simply, it could well be that the load doesn't suit your rifle as I'm assuming that Matt can't really load develop for customers due to practicalities.  There is one other trick left to try.  Find out who shoots this bullet with your barrel length and twist and find what load they developed for it.  Then ask Matt to try the same providing it is within safe parameters.  The bullet is very jump tolerant so keeping it to mag length will be fine.  FWIW my accuracy load is 24.6gr RS50 and the same for N140 both seated to mag length for a 26 inch 1/8 twist 223..

Other than that, try other factory loads at 200 and 300 yds.  If you get one that out performs the one you have then it rules out kit issues and confirms load issues.

Thanks - I'm guessing that could be the case too. I'm hoping to have reloading capability in the not-too-distant future, so it's not the end of the world if I use the remaining HPS ammo for familiarisation with the rifle / recorded use to appease the FEO until then.

I'll maybe pick up some alternative ammo in the meantime if I get the opportunity and also going to work on my prone technique as this can't be doing me any favours. Might crack out the chrono on the next excursion to see if the velocity behaviour has improved now the gun should be broken in.

I've also got a nagging feeling at the back of my mind about the stock's contact with the barrel at the breech end - I'm tempted to crack out the abrasives to get some clearance; although for now will probably content myself with investigating the contact points a bit further. 

[Brummy Mark]

Flyers? what do you call a flyer? An unexplained change in poi for no reason? Or is it a shooter error that you can call your own?

I would go and get a box of factory ammo and a standard bullet for calibre and twist. 

I had a remmy 700 police some years ago, (bought it off flyingfisherman) I spent a while getting an accurate load, nothing special really, circa 1/2moa, but thing was, I could get less than that with cheap privi ammo and also Winchester silver tips were amazing accurate round, never bother wasting my time reloading for that particular rifle.

Then I would hasten to add that shooter error  needs to be explored- you did mention something in one of your posts about being used to  air rifle trigger, if you have been using a pcp air rifle then stepping up to a recoiling CF is a big change and will seriously show up any poor shooting position and highlight inconsistencies. Get someone to critique your positional shooting - obviously make sure that the observer knows what they are looking for against a standard criteria for solid consisted technique of position, hold, trigger control, shot release, recoil management and breathing cycle, etc.

Quote "Position was stable and i was able to hold the crosshairs within 0.5MOA with ease."  So you have a possible  positional stability straight away? - that needs to be taken out of the equation as a priority -  Get a rear bag if your not using one - if you are using one then your shooting position is not as stable as you think - I (and I would hope other marksmen on here) will be used to looking at scope reticle that is rock solid on their intended point of aim - no floating around - and with best technique available trying to follow the shot through as much as possible.

Check and double check everything, especially scope parallax and ocular focusing, do the head bob test up-down, left-right etc as a standard double check.

All the best.

[Catch-22]

I'd echo looking deeper at your technique. If you admit you're not comfortable and maintaining a solid and repeatable position, shot to shot, it will show up on target.

Being able to shoot consistently small groups can only be done with a good technique - regardless of the load.

As stated above, ask a fellow shooter, ideally someone proven to consistently shoot very small groups, to watch and critique your technique and offer some pointers. 

While you're about it, I'd maybe even give them a box of ammunition and ask them to shoot some groups. Having another shooter behind your gun may help to rule out equipment issues and highlight technique instead. Cheaper and quicker than replacing a scope, stock, barrel etc.

Personally, I've seen this happen to someone. They'd spend upwards of £2k on a new AR-15 but couldn't get it to shoot better than 3" at 100m. Frustrated, he asked a couple of us to have a go. All managed to put our 10 round groups into around 0.5", with the best two 5 shot groups being under 0.2". The issue - he was using a monopod (waste of time those!) and was trying to 'free recoil' the rifle, rather than have it seated firmly in his shoulder. Once he addressed these two points, he immediately went on to shoot 0.5-0.7" groups.

[clover]

Thanks chaps!

10 hours ago, Brummy Mark said:

Flyers? what do you call a flyer? An unexplained change in poi for no reason? Or is it a shooter error that you can call your own?

I would go and get a box of factory ammo and a standard bullet for calibre and twist. 

I had a remmy 700 police some years ago, (bought it off flyingfisherman) I spent a while getting an accurate load, nothing special really, circa 1/2moa, but thing was, I could get less than that with cheap privi ammo and also Winchester silver tips were amazing accurate round, never bother wasting my time reloading for that particular rifle.

Then I would hasten to add that shooter error  needs to be explored- you did mention something in one of your posts about being used to  air rifle trigger, if you have been using a pcp air rifle then stepping up to a recoiling CF is a big change and will seriously show up any poor shooting position and highlight inconsistencies. Get someone to critique your positional shooting - obviously make sure that the observer knows what they are looking for against a standard criteria for solid consisted technique of position, hold, trigger control, shot release, recoil management and breathing cycle, etc.

Quote "Position was stable and i was able to hold the crosshairs within 0.5MOA with ease."  So you have a possible  positional stability straight away? - that needs to be taken out of the equation as a priority -  Get a rear bag if your not using one - if you are using one then your shooting position is not as stable as you think - I (and I would hope other marksmen on here) will be used to looking at scope reticle that is rock solid on their intended point of aim - no floating around - and with best technique available trying to follow the shot through as much as possible.

Check and double check everything, especially scope parallax and ocular focusing, do the head bob test up-down, left-right etc as a standard double check.

All the best.

Yes, I'd call a flier a shot outside the group that I can't explain. I did call a few on the last shoot but then I know these are down to me so can be ruled out to an extent. 

I'd guess the 69gn stuff I'm currently using would be fairly standard fare for the 1:8 twist barrel. I see the NRA shop have GGG 69gn stuff so I'll grab a box of that when I'm next at Bisley too. PPU also do a 75gn load but I can't find any of this locally.

tbh I'm wondering if I'm expecting too much from "cheap" ammo, although am loathe to buy any more expensive stuff while I'm unsure of my technique - just found some Hornady match .223 but that's twice the price of the HPS stuff I'm currently using!

Happy to further explore the potential for it to be shooter error; I do have experience with recoiling stuff as I also use a .357 mag lever action, however this is shot standing over much shorter ranges - as such I'm far more familiar with the stance and the expected level of accuracy is a lot less too. Prone shooting with a significantly recoiling gun is a wholly new experience to me.

I was definitely bottom of the experience pile by a long way at Bisley last month - next time I go I'll try and both get some feedback on my technique and see if someone else will shoot some groups with my rifle. I think if there is a problem with technique it will be with recoil management due to inconsistent hold and butt positioning.

My current setup is a Harris bipod up front and a bag at the rear; not that I can see it but I'm getting a fair bit of muzzle rise so I'm guessing the bipod is "hopping"; despite my efforts to pre-load it. I've also noticed that muzzle deflection under recoil is usually fairly unpredictable; always upward but often with left / right components... the way I've dealt with this in the past (with lesser-recoiling guns) is to use a light grip as I've found this is more forgiving than a tight one it's easier to be consistent when allowing the rifle to "free recoil", however appreciate that this is going to be decreasingly viable with heavier-recoiling rifles. 

On the subject of support I've got a Caldwell Deadshot Combo front and rear rest that needs filling (glass beads?) which I'd like to try in preference to the bipod; the 'pod is convenient but I'd always preferred bags when shooting off the bench. I'd be a lot more confident of my abilities off a bench,  however sadly while our range has a fantastic steel example it's not passed for anything larger than .22LR.

Off a bench and bags I can get the crosshairs dead still, realistically prone I'm probably holding within .25 MOA - not perfect but then IMO of little consequence when the rifle is shooting at 1.5-2MOA. Rule out all user error and that's still a 1.25-1.75MOA group.

I think I've got everything related to the rifle setup pegged, thanks - PX was tested as you suggest, everything nice and tight, bore recently cleaned but enough shots to allow it to foul again...

I can't do a lot other than research until I can get back to a range with some more ammo; don't suppose you can recommend any good (preferably online) resources for prone technique? I've found a few on youtube but nothing so far that really starts with the very basics.

Thanks again for your thoughts

2 hours ago, Catch-22 said:

I'd echo looking deeper at your technique. If you admit you're not comfortable and maintaining a solid and repeatable position, shot to shot, it will show up on target.

Being able to shoot consistently small groups can only be done with a good technique - regardless of the load.

As stated above, ask a fellow shooter, ideally someone proven to consistently shoot very small groups, to watch and critique your technique and offer some pointers. 

While you're about it, I'd maybe even give them a box of ammunition and ask them to shoot some groups. Having another shooter behind your gun may help to rule out equipment issues and highlight technique instead. Cheaper and quicker than replacing a scope, stock, barrel etc.

Personally, I've seen this happen to someone. They'd spend upwards of £2k on a new AR-15 but couldn't get it to shoot better than 3" at 100m. Frustrated, he asked a couple of us to have a go. All managed to put our 10 round groups into around 0.5", with the best two 5 shot groups being under 0.2". The issue - he was using a monopod (waste of time those!) and was trying to 'free recoil' the rifle, rather than have it seated firmly in his shoulder. Once he addressed these two points, he immediately went on to shoot 0.5-0.7" groups.

Thanks - most points addressed above but the AR example is somewhat heartening - it's nice to have the effect of poor technique quantified; although I wonder if a massive amount of that wasn't due to the instability of the monopod (what position was he shooting from?). I'd be interested to hear any other tips you might have for increasing consistency when shooting prone!

[Murph]

Did you try hornady 75 gr tap ammunition. Same bullets used as the 75 gr bthp. Shot very well in my 1-9 twist.

 

[clover]

On 12/23/2018 at 1:18 AM, Murph said:

Did you try hornady 75 gr tap ammunition. Same bullets used as the 75 gr bthp. Shot very well in my 1-9 twist.

 

Thanks for the thought - tbh I've struggled to find local suppliers of .223 target ammo; as one would expect most places tend to hold cheap 55/62gn FMJ or soft point hunting loads. I'll keep an eye out for some on my travels though!



So, a year later and finally an update having managed to get back to Bisley.

In addition to what's already been tried / checked to find the source of the issue I've also bought a Caldwell Deadshot Combo rest set to try and rule out the bipod. I've been reading up on / practicing supported prone technique as best as possible; focussing on body position / alignment, butt pad position and loading, trigger control, grip strength and contact area, breathing, relaxation and above all consistency across all these.

Target ammo choice is limited in my part of the world and I'd still got a lot of the HPS Targetmaster left so this was used again for testing. The rifle was set up on the Caldwell bags; the front one sitting on top of a folded blanket to give more elevation.

The bore had been cleaned after the last use and I ran a couple of dry patches through to remove an excess oil that might be present; showing a small amount of black staining in one place - perhaps residual carbon that had since been dissolved by the oil on the final cleaning patch...?

After dialling in +4.75MOA of elevation the first 7 shots at 300yd went into a group of around 1MOA vertical and 2MOA horizontal dispersion. Its centre being around 2MOA right of the POA; suggesting the somewhat variable 9-11 O'clock wind was around 6-7mph from my JBM ballistics calcs.

I held left-edge-of-bull (around 1MOA) for the following three shots; evidently not being quite enough to get them in the middle but closer and into a nice group of around 1MOA with one V-bull and two 4's low-left.

The wind changed to a more 9 O'clock position and I put a further three down, holding on the LHS edge of the 4-ring now so giving around 2MOA windage correction. This yielded a nice just-sub-MOA group slightly high right with one V-bull, one bull and one 4.

I then removed the front rest and blanket, fitted the bipod and put another two shots down - the 4th going a little low right to bring the group to maybe 1.5MOA, the 5th dropping right into the bull with the others. The 4th shot didn't feel like a great release as I was somewhat preoccupied with how the bipod felt a bit less stable than the rest I'd previously been using. 

In summary from the 300yd testing:
- The rifle seems to suffer no POI shift when fired from a clean, cold barrel
- Variable wind notwithstanding the gun seems MOA-capable when I do my bit
- The rifle is more stable on front and rear bags than bipod
- There appears to be little to no difference in POI shift between bag and bipod
 

Inspecting my ammo after the 300yd testing had raised concerns in my mind about the finish on the 69gn SMK's tip - the jacket appearing somewhat ragged and uneven to varying degrees on most examples. After some discussion another club member lent me his multitool and the tips of seven of my remaining ten round were carefully dressed as flat as I could get them (which was a lot better than some had started with!) I left the remaining three most dodgy examples alone as a control.

Next onto 600yd; same setup as before with the front and rear bags and a total of +18MOA elevation adjustment to the scope. Wind had picked up and was now around 10mph I reckon so I held off around 2 Mils / 7MOA to the LHS.

The seven rounds with the dressed tips went into a group of around 1MOA vertical and 3MOA horizontal dispersion, slightly high-right and distributed between the bull and 4 ring. The final three wonky / unmodified rounds went into an evenly-proportioned group of around 0.5 - 0.75MOA high-right across the bull and 4-ring.

In summary from 600yd testing:
- Variable wind notwithstanding the gun seems MOA-capable when I do my bit
- Damage to / variation in the shape of the bullet tip seems to have very little effect on accuracy, as a subsequent internet search corroborated. 


Over the total of 25 rounds fired over both distances the gun seemed very well-behaved. POI being pushed around by the wind but the vertical dispersion suggesting it's capable of MOA-or-better groups in good conditions; and thankfully lacking any of the enormously erroneous (maybe 8 minutes out-of-group) fliers I experienced at this range last time.

IIRC Tikka guarantee that their rifles will hold 1MOA over 5 shots (presumably at 100yd) so I don't view these results as bad at all considering the calibre, wind and range involved; as well as the fact that the gun's totally stock and firing the only brand of ammo I've tried so far. I'd like to think that if I ever get around to reloading some load development might shrink the groups further. 

I'm still not really any wiser as to what cause the fliers last time; the only possible conclusion I can draw is barrel fouling as the problem started at shot 31 last time and I only fired 25 on this occasion. I guess it's subjective, but how many rounds would one expect to get out of a good, clean .223 barrel before accuracy degradation required more cleaning? 

If the problem last time was fouling, is it possible that the the period required between cleaning would increase as the barrel breaks in? As of yesterday the rifle has now consumed 100 rounds.

Thanks again for all the input so far, and as always I'd be interested to read any thoughts anyone might have on this subject