243winxb
Member
http://www.lapua.com/fileadmin/user_upload/esitteet/VihtavuoriInternationalReloguide2008.pdf PDF FILE LINK to loading data PAGE 21. 260 Rem
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I think my rifle has a problem.... (A photo essay)
- Thread starter Afy
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Zak Smith
Member
Afy,
Every barrel is different. Regardless of what the manual states, soot like you're seeing is due to extreme low pressure loads. Also be aware that when you increase cartridge OAL, you increase the initial volume and decrease pressure. According to QuickLoad, going from 2.80 to 2.95" would decrease the max pressure by about 4000 psi. You need to be chronographing these loads, to provide more data about what the gun and load are doing. Also, if you are cleaning very often, the barrel might not be getting an opportunity to "settle down." I know several people whose barrels take 10-30 rounds to settle back to sub-half groups after being cleaned to bare metal.
In short, don't panic. You are loading way under the correct operating range for 260 and it sounds like you're using powders too slow for some of the light bullets you're trying (e.g., 120gr with N160), then blaming it on the rifle. That doesn't make sense. You have multiple clues pointing you in one direction, but you insist the solution lies in the other direction.
-z
Every barrel is different. Regardless of what the manual states, soot like you're seeing is due to extreme low pressure loads. Also be aware that when you increase cartridge OAL, you increase the initial volume and decrease pressure. According to QuickLoad, going from 2.80 to 2.95" would decrease the max pressure by about 4000 psi. You need to be chronographing these loads, to provide more data about what the gun and load are doing. Also, if you are cleaning very often, the barrel might not be getting an opportunity to "settle down." I know several people whose barrels take 10-30 rounds to settle back to sub-half groups after being cleaned to bare metal.
FWIW, according to QuickLoad, a max load at 2.80" with the 120gr SMK is 42.4gr N150, or about 48gr N160 (which won't fit in the case anyway). If you are loading 39.5gr N160 with the 120 SMK, you are WAY UNDERPRESSURE.
In short, don't panic. You are loading way under the correct operating range for 260 and it sounds like you're using powders too slow for some of the light bullets you're trying (e.g., 120gr with N160), then blaming it on the rifle. That doesn't make sense. You have multiple clues pointing you in one direction, but you insist the solution lies in the other direction.
-z
FullEffect1911
Member
Zak,
While I very much believe what you say is true. The fact that federal factory rounds still had the soot problem, and his reloads were perfect out of a friends rifle it seems the problem is more likely the rifle. Now granted I realize one barrel will differ from another in the same chambering, however factory rounds should work. Granted there is a lot of data missing from a chrono, but it seems he has tried a whole lot of different variations with no luck. Also would have been a good idea to try various factory ammo to see what the results were.
however going with the information given, my guess is it is a spec issue in the rifle. It will certainly be interesting to see what the verdict from the maker is.
While I very much believe what you say is true. The fact that federal factory rounds still had the soot problem, and his reloads were perfect out of a friends rifle it seems the problem is more likely the rifle. Now granted I realize one barrel will differ from another in the same chambering, however factory rounds should work. Granted there is a lot of data missing from a chrono, but it seems he has tried a whole lot of different variations with no luck. Also would have been a good idea to try various factory ammo to see what the results were.
however going with the information given, my guess is it is a spec issue in the rifle. It will certainly be interesting to see what the verdict from the maker is.
Zak Smith
Member
It's not unheard-of for some barrels to be "tight" and some to be a little "loose", and for different chambers to be cut for different purposes. If he can load 120's out at 2.90" + and not be hitting the lands, it's almost certainly a long-throated chamber which will reduce pressures considerably. For example, when my 260 barrel was new, I couldn't seat the Lapua 123's or 139's past about 2.810".
I do agree that checking in with the builder would be a good idea at this point, though.
I do agree that checking in with the builder would be a good idea at this point, though.
Zak and everyone who have been so educative and supportive....
I just got back from the builder. I have left the rifle with him. He agrees that there 'might' be an issue with the rifle. He acknowledges that I have only the sixth .260 barrel he has supplied in France and something might not be right.
I also provided him with a sample of the ammunition I have loaded. And he also acknowledges that the groups are unacceptable.
However he will test out the rifle with my ammo, and some he uses to shoot out of his own .260.
Bottom line... he will try and ensure that I am a happy camper. (Which given France's attitude of 'The customer is always wrong') is more than I could ask for.
Worst case sceanrio... I will get a border barrel in 1:8 and put this down to my luck. People who know me do agree that if I didnt have bad luck I would have none at all.
I can load out to 2.913 without hitting the lands across bullet profiles. Dependent on which bullet I am using I start hitting the lands anywhere between .001 and .002 or there abouts.
BTW where can I get quickload? Looks like gven my wierd calibers I do need a copy.
I will hear back from the gunsmith on Tuesday... so I have to contend with shooting my .300 WM or .222 RM this weekend... havent shot the .222 in ages and do need to load up the 600 odd fireformed cases I have.
I just got back from the builder. I have left the rifle with him. He agrees that there 'might' be an issue with the rifle. He acknowledges that I have only the sixth .260 barrel he has supplied in France and something might not be right.
I also provided him with a sample of the ammunition I have loaded. And he also acknowledges that the groups are unacceptable.
However he will test out the rifle with my ammo, and some he uses to shoot out of his own .260.
Bottom line... he will try and ensure that I am a happy camper. (Which given France's attitude of 'The customer is always wrong') is more than I could ask for.
Worst case sceanrio... I will get a border barrel in 1:8 and put this down to my luck. People who know me do agree that if I didnt have bad luck I would have none at all.
I can load out to 2.913 without hitting the lands across bullet profiles. Dependent on which bullet I am using I start hitting the lands anywhere between .001 and .002 or there abouts.
BTW where can I get quickload? Looks like gven my wierd calibers I do need a copy.
I will hear back from the gunsmith on Tuesday... so I have to contend with shooting my .300 WM or .222 RM this weekend... havent shot the .222 in ages and do need to load up the 600 odd fireformed cases I have.
243WINXB:
The Sierra manual lists 39.5gr of N150 as their accuracy load for 120 SMK. Additionally they list it as a compressed load at 2.765 COAL. I used that as the load.
I have played with COAL of 2.70, 2.765, 2.80 and 2.913 with this load. The most accurate groups are posted in this thread. :banghead:
The Sierra manual lists 39.5gr of N150 as their accuracy load for 120 SMK. Additionally they list it as a compressed load at 2.765 COAL. I used that as the load.
I have played with COAL of 2.70, 2.765, 2.80 and 2.913 with this load. The most accurate groups are posted in this thread. :banghead:
rodregier
Member
If the builder wasn't available, I would have suggested slugging the bore and making a chamber cast. You could then measure those to get some indications of dimensions...
NCsmitty
Member
Afy, here's a link to Quickload. http://www.neconos.com/details3.htm
It's my opinion that your 1in9 twist should be near perfect for your 120 grain bullets. The Swedes used a 1in7.5 in their mausers and they shoot the heavier 156 grain RN very accurately but in my experience are not so good with say, 129 gr. bullets or anything lighter. Your 260 is a near twin to the 6.5x55. The problem with all the rounds based on the 7.62x51 is the very short neck. To use heavier bullets, you have to intrude on the powder charge. If you do change to a 1in8 you might need to change to a little heavier bullet for optimum preformance for that twist. I have nearly finished a 6.5x55 on a VZ-24 action with an 26" A&B F54 barrel with a 1in9 twist. Preliminary break in tests with min charge of reloader 19 are encouraging but have not tested it for groups yet. And no soot on the cases, even at the min load level. I plan to shoot nothing heavier than the 123 gr. Scenar, but ya never know. I hope you can get your problem resolved soon.
NCsmitty
It's my opinion that your 1in9 twist should be near perfect for your 120 grain bullets. The Swedes used a 1in7.5 in their mausers and they shoot the heavier 156 grain RN very accurately but in my experience are not so good with say, 129 gr. bullets or anything lighter. Your 260 is a near twin to the 6.5x55. The problem with all the rounds based on the 7.62x51 is the very short neck. To use heavier bullets, you have to intrude on the powder charge. If you do change to a 1in8 you might need to change to a little heavier bullet for optimum preformance for that twist. I have nearly finished a 6.5x55 on a VZ-24 action with an 26" A&B F54 barrel with a 1in9 twist. Preliminary break in tests with min charge of reloader 19 are encouraging but have not tested it for groups yet. And no soot on the cases, even at the min load level. I plan to shoot nothing heavier than the 123 gr. Scenar, but ya never know. I hope you can get your problem resolved soon.
NCsmitty
rodregier
Member
re: chamber casting. I haven't done personally, but it looks simple enough if you prepare properly beforehand.
Cerrosafe from Brownells:
http://www.brownells.com/aspx/NS/store/productdetail.aspx?p=384&st=cerrosafe&s=
$25 for half pound plus shipping.
"There are various products on the market which can be used to make a cast of a gun chamber. To be certain that the product we are offering you is the best and most practical, we contacted the basic manufacturer. They recommended Cerrosafe because of its unique features. Unlike Woodsmetal which swells upon cooling and cannot be removed from a gun chamber, Cerrosafe shrinks during the first 30 minutes of cooling and then at the end of an hour, is EXACTLY chamber size. At the end of 200 hours it will have expanded approximately .0025". This factor is well known by all toolmakers and they will take it into consideration when making dies or reamers or gauges from your cast - if you will tell them the cast is of Cerrosafe. Cerrosafe melts between 158° - 190° F. It should be melted in a clean, iron ladle. Source of heat should be removed as soon as the alloy is completely melted, at which time it is ready to pour. The solidified casting should be removed from the chamber before, or when, it cools to room temperature. If allowed to remain in the mold over an hour, it will grip the chamber walls and be difficult to remove. Clean the chamber of the rifle thoroughly, then plug the bore immediately ahead of the throat with a small rag - but not so tightly it cannot be driven out. If possible, pour the molten Cerrosafe through a small tube into the bottom of the cast, gradually removing the tube as the chamber fills. If the barrel is cold, warm it to room temperature or above before making the cast. When cooled, remove from chamber, using a rod or dowel from the muzzle end of the gun."
From Brownells FAQ:
Q: What sort of equipment do I need to make chamber castings?
A: A good heat source and a container in which to melt the Cerrosafe. You may use a propane torch or a conventional hot air gun to easily melt the Cerrosafe. The melting point for this product is less than boiling water so large heat capacity is not needed. The simplest container we have found is a small food can and it can be held with locking jaw pliers. If a funnel is needed to gain access to the barrel it can be made from a rolled piece of stiff paper or a metal funnel from your other shop uses. A plastic funnel will melt so avoid using that material.
Combining the two suggests using a heat gun, both to pre-heat the barrelled action, and to heat the cerrosafe. A lot safer and gentler than an open flame.
Cerrosafe from Brownells:
http://www.brownells.com/aspx/NS/store/productdetail.aspx?p=384&st=cerrosafe&s=
$25 for half pound plus shipping.
"There are various products on the market which can be used to make a cast of a gun chamber. To be certain that the product we are offering you is the best and most practical, we contacted the basic manufacturer. They recommended Cerrosafe because of its unique features. Unlike Woodsmetal which swells upon cooling and cannot be removed from a gun chamber, Cerrosafe shrinks during the first 30 minutes of cooling and then at the end of an hour, is EXACTLY chamber size. At the end of 200 hours it will have expanded approximately .0025". This factor is well known by all toolmakers and they will take it into consideration when making dies or reamers or gauges from your cast - if you will tell them the cast is of Cerrosafe. Cerrosafe melts between 158° - 190° F. It should be melted in a clean, iron ladle. Source of heat should be removed as soon as the alloy is completely melted, at which time it is ready to pour. The solidified casting should be removed from the chamber before, or when, it cools to room temperature. If allowed to remain in the mold over an hour, it will grip the chamber walls and be difficult to remove. Clean the chamber of the rifle thoroughly, then plug the bore immediately ahead of the throat with a small rag - but not so tightly it cannot be driven out. If possible, pour the molten Cerrosafe through a small tube into the bottom of the cast, gradually removing the tube as the chamber fills. If the barrel is cold, warm it to room temperature or above before making the cast. When cooled, remove from chamber, using a rod or dowel from the muzzle end of the gun."
From Brownells FAQ:
Q: What sort of equipment do I need to make chamber castings?
A: A good heat source and a container in which to melt the Cerrosafe. You may use a propane torch or a conventional hot air gun to easily melt the Cerrosafe. The melting point for this product is less than boiling water so large heat capacity is not needed. The simplest container we have found is a small food can and it can be held with locking jaw pliers. If a funnel is needed to gain access to the barrel it can be made from a rolled piece of stiff paper or a metal funnel from your other shop uses. A plastic funnel will melt so avoid using that material.
Combining the two suggests using a heat gun, both to pre-heat the barrelled action, and to heat the cerrosafe. A lot safer and gentler than an open flame.
rodregier
Member
You can get a rough idea of the bore land height dimension by using a projectile as a gage at the muzzle. It would probably be informative to make the same measurement on your friend's rifle, since they are supposedly using same diameter barrel.
Ideally, to measure the bore diameter (lands and grooves), what you need is a low alloy lead slug that has a diameter slightly larger than the nominal bore groove diameter. Oil the bore and gently drive the slug from the chamber end to the muzzle with a well-fitting cleaning rod with a flat-faced threaded tip. Measure the resulting slug diameter to get the grove diameter. Pure lead is best, but a soft lead alloy can also work. A suitable shotgun buckshot pellet is one way to source the slug. If you don't have suitable tools for measuring such, a good machinist can make the measurement for you on the resulting slug.
#2 buck is nominal diameter of .270"
Ideally, to measure the bore diameter (lands and grooves), what you need is a low alloy lead slug that has a diameter slightly larger than the nominal bore groove diameter. Oil the bore and gently drive the slug from the chamber end to the muzzle with a well-fitting cleaning rod with a flat-faced threaded tip. Measure the resulting slug diameter to get the grove diameter. Pure lead is best, but a soft lead alloy can also work. A suitable shotgun buckshot pellet is one way to source the slug. If you don't have suitable tools for measuring such, a good machinist can make the measurement for you on the resulting slug.
#2 buck is nominal diameter of .270"
243winxb
Member
You have the correct info, mine was wrong in my last post. The problem has to be the rifles chamber.
pike hunter
Member
- Joined
- Jun 1, 2008
- Messages
- 51
Zak Smith
Why do think that is.
I think I have one of those guns.I load up some ammo at different powder weights so many per charge.shot off a whole bunch of ammo working up on charges till i got up to my top charge of the day. shoot groups at .68of a inch at a charge 64.4 of the top of my head.
went home cleaned my gun and load some more rounds.
The next day at the range i shot some more 64.5s that would not even come close to .68 groups of the day before. then I fired some 65s off and was not inpressed buy those either so buy now Im wondering whats going on.
so i press on any ways and shoot some 65.5s and with in so many shot I shot groups at .47 and .46 (all shot at 100yrds).
So if this is the case should I dirty up the barrel before any hunting trip?
and if this is the case Im glad I hand load.
Thanks :
Why do think that is.
I think I have one of those guns.I load up some ammo at different powder weights so many per charge.shot off a whole bunch of ammo working up on charges till i got up to my top charge of the day. shoot groups at .68of a inch at a charge 64.4 of the top of my head.
went home cleaned my gun and load some more rounds.
The next day at the range i shot some more 64.5s that would not even come close to .68 groups of the day before. then I fired some 65s off and was not inpressed buy those either so buy now Im wondering whats going on.
so i press on any ways and shoot some 65.5s and with in so many shot I shot groups at .47 and .46 (all shot at 100yrds).
So if this is the case should I dirty up the barrel before any hunting trip?
and if this is the case Im glad I hand load.
Thanks :
Zak Smith
Member
Patient: It hurts when I poke here.
Doctor: Don't do that!
Doctor: Don't do that!
I don’t believe QuickLoad takes into account how close to the lands you are which makes a difference in pressure. Past a certain seating depth pressure increases as you get closer to the lands. Going away from the lands at first decreases pressure because of gas leakage and the opposite is true also.
I tend to believe what William C. Davis, Jr. says here –
This shows how pressure reacts to seating depth, see page 48. I believe this was used by Harold Vaughn. This link takes a minute to open -
http://deepblue.lib.umich.edu/bitstream/2027.42/3866/5/bac6873.0001.001.pdf
.
Zak Smith
Member
Bullet, based on the max length he can load at and not hit the lands, I was assuming he wasn't loading at or into them.
Zak Smith
My point was that increasing seating depth (longer OAL's) will raise pressures even when not in contact with the lands.
In the link above pressure increased from at least ¼ inch off the lands all the way until contact with the lands. There was not a pressure decrease seating at longer OAL’s as stated by QuickLoad.
My point was that increasing seating depth (longer OAL's) will raise pressures even when not in contact with the lands.
In the link above pressure increased from at least ¼ inch off the lands all the way until contact with the lands. There was not a pressure decrease seating at longer OAL’s as stated by QuickLoad.
Zak Smith
Member
That is an interesting study. I don't know how to resolve its conclusion with the observation that if I load, for example, my 308 longer, I need to add additional powder to maintain the same velocity (the entire range is within 1/4" of the lands).
Zak Smith
I’m no expert but you might try QuickLoad using the same data from the link for the 30-06 and see if it matches the actual measured pressures in the study. If you do please post the results.
A change of 0.025 in seating depth (Longer) would probably increase pressure somewhere around a 500psi (not a lot) but 1/4 inch longer should be around 5,000psi more.
I’m no expert but you might try QuickLoad using the same data from the link for the 30-06 and see if it matches the actual measured pressures in the study. If you do please post the results.
A change of 0.025 in seating depth (Longer) would probably increase pressure somewhere around a 500psi (not a lot) but 1/4 inch longer should be around 5,000psi more.
uk roe hunter
Member
- Joined
- Jun 30, 2006
- Messages
- 350
afy,
any update?
any update?
Zak Smith
Something else.
Look about half way down the page.
From The Lab
“The Effect of Distance From the Lands in Relation to Pressure and Accuracy”
http://www.barnesbullets.com/resources/newsletters/bullet-n-archive/september-2007-barnes-bullet-n/
.
Something else.
Look about half way down the page.
From The Lab
“The Effect of Distance From the Lands in Relation to Pressure and Accuracy”
http://www.barnesbullets.com/resources/newsletters/bullet-n-archive/september-2007-barnes-bullet-n/
.
Zak Smith
Member
Bullet,
Interesting link. Their results, using only one particular bullet, were mixed.
-z
Interesting link. Their results, using only one particular bullet, were mixed.
-z
Sunray
Member
Please reduce the size of your pictures. Big pictures take forever to load for a poster on a dial-up connection.
You need to chamfer the inside of the case mouths and deburr the outside for one thing. Plus the .260 Remington is a hunting cartridge, not a target cartridge. You're getting dandy hunting groups if those are 100 yard groups. The closest you'll get to a match bullet is a Hornady A-Max, if you can get 'em.
If you can't get .260 Rem brass, what are you making it out of?
No offense, but you're trying to make a tack driving target rifle using a deer hunting cartridge.
You need to chamfer the inside of the case mouths and deburr the outside for one thing. Plus the .260 Remington is a hunting cartridge, not a target cartridge. You're getting dandy hunting groups if those are 100 yard groups. The closest you'll get to a match bullet is a Hornady A-Max, if you can get 'em.
If you can't get .260 Rem brass, what are you making it out of?
No offense, but you're trying to make a tack driving target rifle using a deer hunting cartridge.
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