I didn't wanna pirate a current thread so here's my new one. Is there any thing I can do? Obviously I can sight in for coldbore shots but I don't want to compensate for additional shots. I have a fantastic load developped for hot bore. The shots string from cold high to hot low. Everything is tight, medium heavy fluted barrel, full floated. This is a savage fcp-k 110 .300 win mag
What can you do to minimize cold bore/hot bore poi?
- Thread starter fuzzynuts54
- Start date
Like Dogleg said.
If the bbl. is well floated all the way to the reciever, its likely internal stress' thats causing it walk with heat.
Personally, I have never had any success (but lots of $ wasted) trying to tune it away.
Fluting and button-rifling are a recipe for dramatic changes in POI. Precision shooters virtually never use fluted barrels, and it is so much of an issue that some button rifled custom barrel makers even void their warranty if you flute a barrel.
If you want to reduce the probability of wandering POI's, use heavy, and/or shorter barrels, and use cut rifled barrels.
If you want to reduce the probability of wandering POI's, use heavy, and/or shorter barrels, and use cut rifled barrels.
Agreed with all of the above, in my button rifled, medium wt bbl, using a 6.5-270WSM mine went from low to high after about 10 rounds, my next rifle was a heavy bbl 7mm WSM, there is no appreciable change in POI wiht this rifle, despite using the same powder and nearly identical charges.
Both are button rifled, but one is much heavier than the other, I imagine a cut rifled bbl would be even less prone to change of POI as it got hotter,
Both are button rifled, but one is much heavier than the other, I imagine a cut rifled bbl would be even less prone to change of POI as it got hotter,
Hmmm. I did not know that about about fluted. I see on your site kriegers prices, but not the other brands. I'm gonna fiddle with it a little more, I've really only been out a few times with it but have over 200 rounds through. Once it's warmed up it's a sub half moa rifle, and that's good enough for now. However it's about 2" high for first shot and that's unacceptable. My friend is also gonna grab one of those cheap savage packages to start with but also will be upgrading the barrel asap. I also require a muzzle brake, or threaded to accept my factory brake.
Yeah, its hard to give up on a 1/2 moa bbl. without a good fight. Rifles are quirky, every one unique. Only you decide if its worth x amount of cost and effort to bring into line with your expectations. All I'm saying is if its well floated and walks, most likely it always will.
If it's clean cold bore 1'st shot thats the issue,
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try "Lock-ease" as a finisher when you clean. soak a patch & twice through, then 1 dry patch. Seems to imitate a fouled bore for c.c.b. shot.
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Mystic Precision
CGN Ultra frequent flyer
- Location
- Summerland, BC
The issue isn't cut or button rifling but how well the barrel is stressed relieved after the machining is all done.
All quality match barrels are properly stress relieved thus string very little as they heat up.
ALL barrels will eventually do weird things if they get hot enough but most civy shooters will not get a barrel that hot.
F Open with the new magnums in a summer may just be the exception.
I have had the pleasure of shooting a number of factory Savage and Steven barrels in both sporter and heavy contour. Only 1 stayed on course as it heated up. I have also had this with pretty much all the other factory and surplus rifles I have shot over the years.
All the Savages shot well but when the barrel got hot, the groups walked. Yes, I tune my loads for the cold barrel.
I hear that some shooters are having very good results with the Savage F class rigs despite getting the barrels hot. Maybe Savage is doing something a bit different with these barrels. Or the shooters are just lucky.
So if you want consistent, reliable accuracy, a better quality barrel is much more important then the style of rifling. Both shoot well.
Now I also agree that the less mucking you do to the steel the better. Fluting has zero accuracy benefit and very little cooling benefits. It looks good and can reduce the weight of a rig but I prefer to have a contour that best suits the weight and balance desired as opposed to cutting grooves in the steel to loose weight.
however, the fluting on most factory rifles is pretty shallow and really are cosmetic. I don't fault the fluting as the main cause of the stringing. I would just say you have a typical factory barrel.
Either change the barrel or consider reducing the number of shots in a string before letting it cool.
Or sending a few downrange to heat up the barrel, then shoot for 'score'.
Another thought is the alum chassis. I have not been very pleased with how the accustock actually beds the action. Great concept, not so good in the 'flesh'. Bedding has solved alot of issues for the rifles that I have worked on. These rifles are now shooting consistently from a cold bore.
Not saying that this will solve your stringing as it could be a barrel issue and that's it, but something to consider.
No matter how tight you twist those action bolts, the chassis does not adequately support the action and it will move. to check, just take the action out of the stock and have at look on the bottom of the action. I bet some of the bluing is now missing and you have 2 thin grey lines on either sides of the mag opening. A shiny spot just in front of the rear action screw hole. And a wide rectangle on the front of the recoil lug.
if you run your finger over these grey areas, you will rub off some dust - that would be a mixture of powdered alum and bluing
There is also a possibility that the chassis is not level to the action and you may bend the action sligthly when the action bolts are tightened. NO way this is good for consistency.
These are some of the problem areas that I have seen in the stocks/rifles I have bedded. The rifles seem to be shooting great now.
YMMV.
Jerry
All quality match barrels are properly stress relieved thus string very little as they heat up.
ALL barrels will eventually do weird things if they get hot enough but most civy shooters will not get a barrel that hot.
F Open with the new magnums in a summer may just be the exception.
I have had the pleasure of shooting a number of factory Savage and Steven barrels in both sporter and heavy contour. Only 1 stayed on course as it heated up. I have also had this with pretty much all the other factory and surplus rifles I have shot over the years.
All the Savages shot well but when the barrel got hot, the groups walked. Yes, I tune my loads for the cold barrel.
I hear that some shooters are having very good results with the Savage F class rigs despite getting the barrels hot. Maybe Savage is doing something a bit different with these barrels. Or the shooters are just lucky.
So if you want consistent, reliable accuracy, a better quality barrel is much more important then the style of rifling. Both shoot well.
Now I also agree that the less mucking you do to the steel the better. Fluting has zero accuracy benefit and very little cooling benefits. It looks good and can reduce the weight of a rig but I prefer to have a contour that best suits the weight and balance desired as opposed to cutting grooves in the steel to loose weight.
however, the fluting on most factory rifles is pretty shallow and really are cosmetic. I don't fault the fluting as the main cause of the stringing. I would just say you have a typical factory barrel.
Either change the barrel or consider reducing the number of shots in a string before letting it cool.
Or sending a few downrange to heat up the barrel, then shoot for 'score'.
Another thought is the alum chassis. I have not been very pleased with how the accustock actually beds the action. Great concept, not so good in the 'flesh'. Bedding has solved alot of issues for the rifles that I have worked on. These rifles are now shooting consistently from a cold bore.
Not saying that this will solve your stringing as it could be a barrel issue and that's it, but something to consider.
No matter how tight you twist those action bolts, the chassis does not adequately support the action and it will move. to check, just take the action out of the stock and have at look on the bottom of the action. I bet some of the bluing is now missing and you have 2 thin grey lines on either sides of the mag opening. A shiny spot just in front of the rear action screw hole. And a wide rectangle on the front of the recoil lug.
if you run your finger over these grey areas, you will rub off some dust - that would be a mixture of powdered alum and bluing
There is also a possibility that the chassis is not level to the action and you may bend the action sligthly when the action bolts are tightened. NO way this is good for consistency.
These are some of the problem areas that I have seen in the stocks/rifles I have bedded. The rifles seem to be shooting great now.
YMMV.
Jerry
I'll try the bedding, I'll lay a couple thicknesses of tape on the sides of the action, lay the filler in then snug it up. When it's hardned and the tape out it should be free and clear of any possable twisting of the action. I blast this thing like it was a .22, burning the barrel off. I'll shoot 100 rounds In an hour easy. I'm kinda thinking some of the problem is that I get the front of the receiver so hot so fast that the heat hasn't made it to the rear yet, therefore steel expands with heat, raises the front of the scope relative to the bore, hence lowering poi continuously as it expands more and more until it maxes out. You might think the rear of the receiver would heat up, expand and even out but it hardly gets warm, while the front and chamber area are got enough to burn skin. I didn't want a fluted barrel but that's the only way I could get a heavier barrel with muzzlebrake from savage in my price range
Jerry, I agree that all good barrels go through a process of stress relief, but I am here to tell you that no stress relieving process removes 100% of latent stresses. Even barrels used in cut rifled barrels retains some measure of stress, but it is nothing compared to that to which buttoned - and in particular hammer forged - barrels go through.
I had a great conversation with a gun builder during last years' BC Provincials and he was telling me about how a (brand not important)US made, stress-relieved button rifled custom match barrel that had minimal run-out had actually clamped onto his blade while he was cutting one down for length, and ended up with significant (I can't remember what he said) run-out after the cut.
This is not to say that button rifled barrels do not shot well - quite the opposite. Ted Gaillard builds some of the best buttoned barrels in the world and I would put his up against any simliarly built barrel. It is a fact of manufacturing life however, that the issue of latent stress and elastic recoil produce more abberations, and is why many button barrel makers sell different grades of barrel, because the end results are sometimes flawed to a small degree. It also accounts for the issues of walking POI,s which you have acknowledged can be a problem. I currently do not have that problem in 20 round+sighter strings.
I am certainly not getting into the "this brand is better" minefield, because that is a no-win argument, I am just pointing out that there is sometimes a price to be paid for the faster cheaper process of building barrels. I have shot some of my best scores with button-rifled barrels. They can be a damned fine product.
I had a great conversation with a gun builder during last years' BC Provincials and he was telling me about how a (brand not important)US made, stress-relieved button rifled custom match barrel that had minimal run-out had actually clamped onto his blade while he was cutting one down for length, and ended up with significant (I can't remember what he said) run-out after the cut.
This is not to say that button rifled barrels do not shot well - quite the opposite. Ted Gaillard builds some of the best buttoned barrels in the world and I would put his up against any simliarly built barrel. It is a fact of manufacturing life however, that the issue of latent stress and elastic recoil produce more abberations, and is why many button barrel makers sell different grades of barrel, because the end results are sometimes flawed to a small degree. It also accounts for the issues of walking POI,s which you have acknowledged can be a problem. I currently do not have that problem in 20 round+sighter strings.
I am certainly not getting into the "this brand is better" minefield, because that is a no-win argument, I am just pointing out that there is sometimes a price to be paid for the faster cheaper process of building barrels. I have shot some of my best scores with button-rifled barrels. They can be a damned fine product.
If you think stress relieving your barrel will reduce the POI shift on your barrel I know a tool and die maker with a low frequency stress reliever.Apparently the machine is used in the aircraft industry ,he uses it on crankshafts and such.
I have allways thought it would be cool to try his machine on a problem barrel.
I have allways thought it would be cool to try his machine on a problem barrel.
Mystic Precision
CGN Ultra frequent flyer
- Location
- Summerland, BC
Obtunded, as you know, I have never said one method of barrel rifling is better then the other. Both have made duds and screamers. That is the nature of manf. And yes, I have shot both styles of rifling from a variety of manf.
If there was a clear better process, that process would be universal. Both styles (and hammer forged barrels) of rifling have been used in making match barrels for how many decades? With the tens of thousands contested these many years, I think someone would have figured out a trend.
Quality barrel makers take the steps to ensure that their highest grade barrels meet certain lofty specs. Their reputation and survival depends on maintaining that level of performance.
Shilen is one of the oldest and largest supplier of match quality barrels in the world. And they have produced barrels that hold a variety of world records. They have consulted in the setup and building of new factories in other parts of the world. They might be doing something right?????
So whether a method has a 5% falldown or 8%, really doesn't matter as long as those barrels offered as top grade are exactly that.
Just because a company doesn't offer grade 2 to the shooting public doesn't mean that company doesn't produce duds. All manufacturing has a degree of falldown. Its the QC that catches the duds that matters.
There are so many 'world' records held by BOTH styles of rifling and from a wide range of manf, that anyone saying a brand is the very best isn't being accurate (like that?)
A good barrel is a good barrel and crap is crap. If all the holes in the target go where you expect, then you have made a great barrel purchase and it is up to your skills at reading the wind that will determine the standings.
YMMV
Jerry
If there was a clear better process, that process would be universal. Both styles (and hammer forged barrels) of rifling have been used in making match barrels for how many decades? With the tens of thousands contested these many years, I think someone would have figured out a trend.
Quality barrel makers take the steps to ensure that their highest grade barrels meet certain lofty specs. Their reputation and survival depends on maintaining that level of performance.
Shilen is one of the oldest and largest supplier of match quality barrels in the world. And they have produced barrels that hold a variety of world records. They have consulted in the setup and building of new factories in other parts of the world. They might be doing something right?????
So whether a method has a 5% falldown or 8%, really doesn't matter as long as those barrels offered as top grade are exactly that.
Just because a company doesn't offer grade 2 to the shooting public doesn't mean that company doesn't produce duds. All manufacturing has a degree of falldown. Its the QC that catches the duds that matters.
There are so many 'world' records held by BOTH styles of rifling and from a wide range of manf, that anyone saying a brand is the very best isn't being accurate (like that?)
A good barrel is a good barrel and crap is crap. If all the holes in the target go where you expect, then you have made a great barrel purchase and it is up to your skills at reading the wind that will determine the standings.
YMMV
Jerry
Mystic Precision
CGN Ultra frequent flyer
- Location
- Summerland, BC
Although I don't see their ads anymore, cryogenic stress relieving was supposed to be a method to do just that. I know it is used in industrial tooling so there are grounds for success.
However, never seeing any option in Canada, I have never pursued it.
Plus the cost of stress relieving a factory barrel doesn't seem to make alot of economic sense unless that was the only barrel one had access to.
Would love to hear if someone has been able to gain better performance by stress relieving a barrel.
Jerry
That's an interesting argument about the heat only affecting the front part of the base. I guess the steel just isn't transferring the heat as efficiently as we'd expect. Another thing I've found is the actual chamber stays cool because the brass carries away almost all the heat from that area.
Mystic Precision
CGN Ultra frequent flyer
- Location
- Summerland, BC
am, if the exterior of the barrel/action is hot enough to burn your skin, within a second the chamber will be that hot.
That is why ammo can cook off if left in high rate of fire guns. Machine guns tend to be open bolt for this reason.
I have seen some amazingly accurate Tikka and these are all hammer forged me thinks.
Aren't AI barrels hammer forged too????
It is not how they are made. It is how WELL they are made.
Jerry
That is why ammo can cook off if left in high rate of fire guns. Machine guns tend to be open bolt for this reason.
I have seen some amazingly accurate Tikka and these are all hammer forged me thinks.
Aren't AI barrels hammer forged too????
It is not how they are made. It is how WELL they are made.
Jerry
rnbra-shooter
CGN Ultra frequent flyer
- Location
- New Brunswick
Is this strictly a cold-vs-warm bore phenomenon? (i.e. not clean-vs-dirty; you're talking about a cold dirty bore vs. a hot dirty bore?)
After shot #1 has landed an inch high, does shot #2 go into the group that will be formed by shots 3-10? Or does it take several shots to "walk" into the main group?
After shot #1 has landed an inch high, does shot #2 go into the group that will be formed by shots 3-10? Or does it take several shots to "walk" into the main group?
It's only a cold vs hot. They walk directly down digressively. Each lower than the last yet spacing is tighter untill it it reaches as max and then it settles into some fine groups. .24 to just under half inch consistently but only after 6 or so to heat it up. Let it cool ten min and next shot is high.
rnbra-shooter
CGN Ultra frequent flyer
- Location
- New Brunswick
Sorry for the delay, have been away. It sure sounds like you have some sort of residual stress in your barrel/action/bedding that is "brought out" by a change of temperature. You can either learn to live with it (perhaps you can measure and "calibrate" it, or you can hunt it down (e.g. change barrel or re-install barrel, tweak the torque on your front and/or rear bedding screw, etc.
I got an extraordinarily bad 300WM barrel on a used Savage FCXP3 or whatever that combo of letters is on the package rifles with detachable mag. The third shot would be 6" higher at 200 yards. I ended up switching barrels to a heavier factory barrel and now I can shoot 5 shots in a row and print a good group (3/4" at 100 yards).
