devon deer stalker
Well-Known Member
Not on this site i suspect!
consistent odd grouping
- Thread starter Mungo
- Start date
or worst case measure.... before cutting. M6 has 1mm pitch. Count revolutions easy to see/measure if she is bottoming out.
edi
As I understand it, count the revolutions as you take the action out and then turn the screw the same number of revolutions into the bare action and see if touches down.
I just had a thought, are these screws different lengths and if so put them in the other way?
David.
I just had a thought, are these screws different lengths and if so put them in the other way?
David.
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Is there any space between the action and stock for some shims to prevent movement? Are you still able to move barrel easily in barrel channel? Bits of margarine tub/coke can will work. Is there space for a shim next to recoil lug? Are you tightening the action screws enough? Just my 2p. If that doesn't work I'll take it off your hands cheap in a year or so....
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Heym SR20
Well-Known Member
To see if the action screws are bottoming out. Turn rifle over and remove action screw, but hold action tightly into stock. Using a depth guage or failing a stright thin piece of stick / wire measure to the bottom of the hole to outside face of bottom metal. Compare this to length of screw. If it's longer take a wee bit off with a file.
Toxster
Well-Known Member
I'm inclined to ask if this is Stalking rifle and it hits first time on the exact point of aim, is there much to worry about? Especially if the movement is so predicatable that any follow-up shot can be compensated for.
I had something similar and it was that the front lug had a tiny bit of movement, a shim sorted it dramatically, though shimming a bedded rifle feels wrong.
If there's nothing obvious and bedding a scope issue shave been ruled out I'd be tempted to look to coppering. A deep clean and adopting a polishing regime might keep the barrel going a bit longer.
Not to be too cheeky but..... do your other rifles exhibit the same behaviour....?
I had something similar and it was that the front lug had a tiny bit of movement, a shim sorted it dramatically, though shimming a bedded rifle feels wrong.
If there's nothing obvious and bedding a scope issue shave been ruled out I'd be tempted to look to coppering. A deep clean and adopting a polishing regime might keep the barrel going a bit longer.
Not to be too cheeky but..... do your other rifles exhibit the same behaviour....?
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First shot from cold bore no longer goes to point of aim (see pics posted last night).
As said previously, deep cleaning has very little effect on grouping or POI with this rifle.
And no, my other rifles do not show similar patterns. I shoot consistent groups of around an inch with both 308 and 270. The 308 is capable of more, and I can manage that on a good day. When I shot the strings posted above last night, i was also shooting the 308 as a sanity check, and managed comfortably sub-1" groups.
As said previously, deep cleaning has very little effect on grouping or POI with this rifle.
And no, my other rifles do not show similar patterns. I shoot consistent groups of around an inch with both 308 and 270. The 308 is capable of more, and I can manage that on a good day. When I shot the strings posted above last night, i was also shooting the 308 as a sanity check, and managed comfortably sub-1" groups.
long_range_rob
Well-Known Member
Its not the best job I have seen.
I have eave known many people have problems with .243 grouping due to overly heavy bullet choice. The cartridge was designed for 70gn projectiles and Sako rifle theirs for these bullet weights. My 75 Varmint shoots 70gn pills into 0.5 inch groups and 100gn bullets in to 2" groups. Both are acceptable for "Hunting" accuracy but I know which one inspires more confidence.
bewsher500
Well-Known Member
Its not the best job I have seen.
I have eave known many people have problems with .243 grouping due to overly heavy bullet choice. The cartridge was designed for 70gn projectiles and Sako rifle theirs for these bullet weights. My 75 Varmint shoots 70gn pills into 0.5 inch groups and 100gn bullets in to 2" groups. Both are acceptable for "Hunting" accuracy but I know which one inspires more confidence.
most factory barreled 243s, including sako are 1:10" twist
this is fine for 100gr and arguably even for 105 gr
BUT you need to stick to flat base spitzer design bullets or run the gauntlet of stability vs MV
100gr boat tail ballistic tips can be too LONG for a 1:10"
flytie
Well-Known Member
Mungo,
If your rifle has had a full bedding job, with pillars and glass, then it would be worth while torquing the screws to 35 inch-lbs (not ft-lbs), as recommended by Nathan Foster in his splendid book, The Practical Guide To Bolt Action Rifle Accurizing & Maintenance.
Now for some good news, you have in your Sako 75 III a very highly regarded action, so much so that many rifle-smiths snap them up as soon as a shot out action appears on the market. You have already had a bedding job done on the rifle, so if the worst comes to the worst have it re-barrelled and you will have an extremely accurate rifle which will give you many years of service.
Oddly, and I cannot understand why, there are two Sako 75 III action .243's for sale on this site that have not shifted for many months. A shot out action seems to fetch somewhere between £350 to £450, if you are tempted to sell. But before you do, think about those rifle-smiths waiting to snap up your action. Why do they want them?
I have made a little study of Sako 75 actions, having stupidly sold one and having to get rid of the other to fund my divorce, using a felt marker pen I have coloured in the backs of nine sets of bolt lugs that friends have let me examine, and have yet to find one where all three lugs do not come into good contact with the action. Try the same experiment with some two lug actions sometime and see how many just have one lug contacting the action! It might horrify you.
So with a very good action, a (hopefully) fully bedded stock all you will need is a re-barrel job to give you an extremely accurate semi-custom rifle.
Bon chance, Simon
If your rifle has had a full bedding job, with pillars and glass, then it would be worth while torquing the screws to 35 inch-lbs (not ft-lbs), as recommended by Nathan Foster in his splendid book, The Practical Guide To Bolt Action Rifle Accurizing & Maintenance.
Now for some good news, you have in your Sako 75 III a very highly regarded action, so much so that many rifle-smiths snap them up as soon as a shot out action appears on the market. You have already had a bedding job done on the rifle, so if the worst comes to the worst have it re-barrelled and you will have an extremely accurate rifle which will give you many years of service.
Oddly, and I cannot understand why, there are two Sako 75 III action .243's for sale on this site that have not shifted for many months. A shot out action seems to fetch somewhere between £350 to £450, if you are tempted to sell. But before you do, think about those rifle-smiths waiting to snap up your action. Why do they want them?
I have made a little study of Sako 75 actions, having stupidly sold one and having to get rid of the other to fund my divorce, using a felt marker pen I have coloured in the backs of nine sets of bolt lugs that friends have let me examine, and have yet to find one where all three lugs do not come into good contact with the action. Try the same experiment with some two lug actions sometime and see how many just have one lug contacting the action! It might horrify you.
So with a very good action, a (hopefully) fully bedded stock all you will need is a re-barrel job to give you an extremely accurate semi-custom rifle.
Bon chance, Simon
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This is only my opinion based entirely on personal experience.
I'm not an expert in anything, but I can't understand the general ambivalence to bore scoping the barrel when we get problems like this. It's like we all go into denial, 'can't be the barrel...' - I know I did. I bought a Tikka M595 in .243 from a friend that had genuinely had less than 500 rounds through it. It soon began shooting an identical pattern to the photo in post #36. I got tons of great advice, bedding, barrel/stock interference, ammo, technique, scope, mounts, moderator etc. It was all genuine, well intentioned and came from some very knowledgable people. It's fantastic to see the amount of genuine help and advice offered on here and to me at the time by my mates.
Another very knowledgable friend bore scoped it but concetrated on the muzzle end - didn't look at the throat. I took a look from the chamber while he went to get a cuppa - it looked terrible, cracked, crazed and riddled with copper. With hindsight, the OAL should have given me a clue, longer than it should have been. The fact that wet patches never actually stopped bringing copper out also rang alarm bells. A bit of internet research educated me on how big a problem throat erosion is with calibres like .243.
In the end I got fed up, took it to Mike at Calton Moor, he bore scoped it and we got it re-barreled. It went back on the same action on the original bedding in the same stock with the same scope & mounts. Shoots perfect with the same home load ammo.
The lesson I took from my experience is that barrels are 'consumable items', they are subject to frankly mind boggling temperatures, pressures and chemical cocktails, so perhaps we shouldn't expect them to last for ever. Even relatively low shot counts can, given certain circumstances (particularly letting barrels get hot), cause serious internal damage.
I'm sure some will disagree with what I say, thats fair enough, we all have our opinions, this is just my recent painful personal experience.
I hope your barrel is ok, in the end mine cost more than i paid for the rifle, but I reckon bore scoping would be sensible, if only to rule these issues out. Is there anyone close by who has a bore scope who could help out?
I'm not an expert in anything, but I can't understand the general ambivalence to bore scoping the barrel when we get problems like this. It's like we all go into denial, 'can't be the barrel...' - I know I did. I bought a Tikka M595 in .243 from a friend that had genuinely had less than 500 rounds through it. It soon began shooting an identical pattern to the photo in post #36. I got tons of great advice, bedding, barrel/stock interference, ammo, technique, scope, mounts, moderator etc. It was all genuine, well intentioned and came from some very knowledgable people. It's fantastic to see the amount of genuine help and advice offered on here and to me at the time by my mates.
Another very knowledgable friend bore scoped it but concetrated on the muzzle end - didn't look at the throat. I took a look from the chamber while he went to get a cuppa - it looked terrible, cracked, crazed and riddled with copper. With hindsight, the OAL should have given me a clue, longer than it should have been. The fact that wet patches never actually stopped bringing copper out also rang alarm bells. A bit of internet research educated me on how big a problem throat erosion is with calibres like .243.
In the end I got fed up, took it to Mike at Calton Moor, he bore scoped it and we got it re-barreled. It went back on the same action on the original bedding in the same stock with the same scope & mounts. Shoots perfect with the same home load ammo.
The lesson I took from my experience is that barrels are 'consumable items', they are subject to frankly mind boggling temperatures, pressures and chemical cocktails, so perhaps we shouldn't expect them to last for ever. Even relatively low shot counts can, given certain circumstances (particularly letting barrels get hot), cause serious internal damage.
I'm sure some will disagree with what I say, thats fair enough, we all have our opinions, this is just my recent painful personal experience.
I hope your barrel is ok, in the end mine cost more than i paid for the rifle, but I reckon bore scoping would be sensible, if only to rule these issues out. Is there anyone close by who has a bore scope who could help out?
bewsher500
Well-Known Member
The problem is....bores that look horrible don't always shoot badly..
bores that look great don't always shoot great!
i had a .222 that had a section of rifling that was so corroded it was basically a crater
bloody thing shot everything I fed it!
bores that look great don't always shoot great!
i had a .222 that had a section of rifling that was so corroded it was basically a crater
bloody thing shot everything I fed it!
Sorry for the late reply, like Kalahari said.
Count the revolutions that the screws go into the action without stock. When tightening the action in the stock you must have slightly less revolutions until tight and torqued down otherwise you are not clamping the stock between action and bottom metal.
One thing that is often forgotten, a barrel change might be quite expensive especially when fitting a good match barrel but then you might have a rifle which is so good that will never sell it. You could also change calibre while you are at it.... nice 7-08 perhaps...
edi
Yes - I've thought a lot about a 7-08. If getting variations wasn't such a ballache, I'd probably be very inclined to do that.
However, i'm not yet convinced it isn't the bedding, and there's no point paying the £6-700 for a barrel, only to find there's STILL a problem!
Take a close look at this pic: I really worry that the voids here are bad news...
View attachment 69432
Toxster
Well-Known Member
Sounds pretty bodgy..... Looks not much better.
Be interested to know how many rounds have been down that barrel. Re-barrel might be simplest or just accept that the first shot is on target first time and use accordingly. Could just send it to Brock and Norris with a note saying "fix this."
My call would be to bung Gunstar and use the .308 until the funds for a re-barrel or replacement are saved up, or just stick with .308.
Be interested to know how many rounds have been down that barrel. Re-barrel might be simplest or just accept that the first shot is on target first time and use accordingly. Could just send it to Brock and Norris with a note saying "fix this."
My call would be to bung Gunstar and use the .308 until the funds for a re-barrel or replacement are saved up, or just stick with .308.
sundog
Well-Known Member
I'm no expert but I have to say Mungo that I think it's your barrel and not the bedding. Although the bedding doesn't look the best job it does appear to be doing the job in that around the recoil lug looks good and well formed.
I bought a Sako 75 ex estate rifle off my old boss a number of years ago for a very good price. It was in reasonable nick and the barrel didn't look too bad but hadn't been treated with any care; it was just a tool. I took it home gave it the cleaning of its life and it was shooting inch to inch and a half groups that I wasn't particularly happy with like this:
View attachment 69435View attachment 69437
These were norma rounds with the nosler ballistic tips so I got a few other makes off a mate to see if a different brand would do better. They all shot much the same apart from a handful of old unidentified norma rounds which did this:
View attachment 69438
With hindsight this was the worst result that I could have got as it sent me on a wild goose chase to find the 'magic bullet'. I tried everything to get the same kind of grouping again but in doing so I noticed that after a clean the first few shots were wild then they seemed to tighten and then went wild again. I eventually decided to take the rifle to Russel Gall in Mintlaw and when we borescoped the barrel it was in a mess and Russel explained that the first few shots after a clean smoothed out the bore with copper from the bullet but accuracy would be terrible, then the next few shots would be good and then it would all go to hell again as the barrel was fouling too much.
I decided to get Russel to rebarrel it and I must say he did a fantastic job on it. It now does this at 110m:
View attachment 69441
I feel your pain Mungo. Best of luck
I still think it's your Barrel
I bought a Sako 75 ex estate rifle off my old boss a number of years ago for a very good price. It was in reasonable nick and the barrel didn't look too bad but hadn't been treated with any care; it was just a tool. I took it home gave it the cleaning of its life and it was shooting inch to inch and a half groups that I wasn't particularly happy with like this:
View attachment 69435View attachment 69437
These were norma rounds with the nosler ballistic tips so I got a few other makes off a mate to see if a different brand would do better. They all shot much the same apart from a handful of old unidentified norma rounds which did this:
View attachment 69438
With hindsight this was the worst result that I could have got as it sent me on a wild goose chase to find the 'magic bullet'. I tried everything to get the same kind of grouping again but in doing so I noticed that after a clean the first few shots were wild then they seemed to tighten and then went wild again. I eventually decided to take the rifle to Russel Gall in Mintlaw and when we borescoped the barrel it was in a mess and Russel explained that the first few shots after a clean smoothed out the bore with copper from the bullet but accuracy would be terrible, then the next few shots would be good and then it would all go to hell again as the barrel was fouling too much.
I decided to get Russel to rebarrel it and I must say he did a fantastic job on it. It now does this at 110m:
View attachment 69441
I feel your pain Mungo. Best of luck
I still think it's your Barrel
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Had similar issues with my Sako 85 using 70gr Nosler BT's. 1st shot approx 2" at 2 o'clock, subsequent shots spot on & approx 1/2moa. Recently changed to Sierra Blitzking 70gr & the problem solved. Still don't know if the problem was me, the rile, ammunition or a combination. Nodler BT's in other calibres/weights I still swear by. One of life's mysteries!
So a new thing to worry about: it has been suggested that my experiment with a shim may have damaged the bedding!
The argument is that this caused the barrel to exert tension on the bedding, which could crack it or cause it to come away from the wood.
I find this hard to believe - any opinions?
The argument is that this caused the barrel to exert tension on the bedding, which could crack it or cause it to come away from the wood.
I find this hard to believe - any opinions?
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