Looking for Ballistics data for 6.5mm Berger 130 gn VLD Hunting

[SigSavage]

I bought a T3 HB from a guy who figured out the sweet spot for load data, but he didn't tell me any velocity numbers before he deleted them from his calculator. Without buying the Berger book, or a chrony I'm kinda at a loss for some ballpark numbers. If someone here has some starting points, I would greatly appreciate it.

I'm using a 6.5x55 Swedish with a 23.6" barrel 1:8 twist.

His load: Powder is 46.5gn of IMR 4831 pushing a 130gn VLD Berger Hunting bullet.

Thanks for any insight.

 

[DocUSMCRetired]

We have a free online calculator: http://appliedballisticsllc.com/ballistics/

 

[SigSavage]

We have a free online calculator: http://appliedballisticsllc.com/ballistics/

Yes, thanks. But it is the muzzle velocity that I need to use such a calculator. This is what I am looking for.

 

[barefooter56]

I bought a T3 HB from a guy who figured out the sweet spot for load data, but he didn't tell me any velocity numbers before he deleted them from his calculator. Without buying the Berger book, or a chrony I'm kinda at a loss for some ballpark numbers. If someone here has some starting points, I would greatly appreciate it.

I'm using a 6.5x55 Swedish with a 23.6" barrel 1:8 twist.

His load: Powder is 46.5gn of IMR 4831 pushing a 130gn VLD Berger Hunting bullet.

Thanks for any insight.

SigSavage,
For IMR 4831 we show :
Minimum = 41.5 grains , Maximum = 43.9 grains APPROX velocities are 2628 to 2770 fps. these are based on a COAL of
3.150 inches. Kind of looks like he MAY be setting the bullet out twords the lands some. I hate to tell you but you're probabaly going to have to find your seating depth to the lands . Then find your seating depth accuracy node . Then work the load back up.
We suggest you test at .010 off then .050 off then .090 off and then .130 off the lands. We found that these were the seating depths that got us "close to" or "on to" a seating depth accuracy node. If you think you're close and want to tweak the seating depth and test. Go .005 to .010 to either side of the CBTO ( cartridge base to ogive) measurement that showed the most promise. Please do all this at the lowest powder charge listed. If you have any more questions please contact us either here or at techsupport@bergerbullets.com

 

[SigSavage]

SigSavage,
For IMR 4831 we show :
Minimum = 41.5 grains , Maximum = 43.9 grains APPROX velocities are 2628 to 2770 fps. these are based on a COAL of
3.150 inches. Kind of looks like he MAY be setting the bullet out twords the lands some. I hate to tell you but you're probabaly going to have to find your seating depth to the lands . Then find your seating depth accuracy node . Then work the load back up.
We suggest you test at .010 off then .050 off then .090 off and then .130 off the lands. We found that these were the seating depths that got us "close to" or "on to" a seating depth accuracy node. If you think you're close and want to tweak the seating depth and test. Go .005 to .010 to either side of the CBTO ( cartridge base to ogive) measurement that showed the most promise. Please do all this at the lowest powder charge listed. If you have any more questions please contact us either here or at techsupport@bergerbullets.com

Thanks for the info. His data is as follows (as measured by me on my equipment of his reference dummy round)

COAL: 2.979" which is 0.025" off the lands
Cartridge length to Ogive: 2.332"

I'm not sure what to do about this load he used that is higher than your max. This guy definitely knows his stuff, so I have a lot of confidence in his testing.

I should mention that he had a gunsmith cut a new chamber with a shorter throat using a match reamer to bring the bullet closer to the lands, so his COAL will reflect this compared to your COAL/ Max COAL. This set the barrel back about 1/4". The way I understand it is that Tikka tends to cut North American chambers longer than the European counterparts because we like to set the bullet farther from the lands or something. It was cut specifically to fit this bullet, anyway. I may be totally misremembering as to the why, but it is what it is now. It's more accurate this way without having to set the bullet 1/4" further forward. So I am led to believe..... I'm new to all this stuff, so I could have my facts wrong. I know I'm right on the chamber size though- got that from the horse's mouth.

 

[barefooter56]

Thanks for the info. His data is as follows (as measured by me on my equipment of his reference dummy round)

COAL: 2.979" which is 0.025" off the lands
Cartridge length to Ogive: 2.332"

I'm not sure what to do about this load he used that is higher than your max. This guy definitely knows his stuff, so I have a lot of confidence in his testing.

I should mention that he had a gunsmith cut a new chamber with a shorter throat using a match reamer to bring the bullet closer to the lands, so his COAL will reflect this compared to your COAL/ Max COAL. This set the barrel back about 1/4". The way I understand it is that Tikka tends to cut North American chambers longer than the European counterparts because we like to set the bullet farther from the lands or something. It was cut specifically to fit this bullet, anyway. I may be totally misremembering as to the why, but it is what it is now. It's more accurate this way without having to set the bullet 1/4" further forward. So I am led to believe..... I'm new to all this stuff, so I could have my facts wrong. I know I'm right on the chamber size though- got that from the horse's mouth.

SigSavage,
The difference in throat length between rifles manufactured for America and rifles manufactured for Europe probably has a lot more to do with lawyers than anything. In their world of "loser pays" there isnt much tendency to litigate. IF the barrel was set back and re-chambered like you say then unless the load information you have was done after that it MAY be valid. If it was done before the chamber change it is not. Since you are dealing with incomplete information here . I would suggest you do your own load testing to find your accuracy nodes and not try to take a short cut that may end in tears. The COAL I listed was it the bullet tip to base of the cartridge case measurement. Load up a dummy round to the 3.150 COAL then measure the round with a comparator to see what the CBTO is and compare it to your information if you want to see if its close , short, long to your 2.332. But if it was me. I would make a dummy round to the lands , re-find the seating depth sweet spot using the "VLDS, making them shoot" found in the TECH TALK section on our website at the lowest powder charge listed. Then work the load back up slowly checking for pressure signs and accuracy as you increase the powder charge till you find your velocity accuracy node. Sometimes its safer to just start all over.

 

[SigSavage]

SigSavage,
The difference in throat length between rifles manufactured for America and rifles manufactured for Europe probably has a lot more to do with lawyers than anything. In their world of "loser pays" there isnt much tendency to litigate. IF the barrel was set back and re-chambered like you say then unless the load information you have was done after that it MAY be valid. If it was done before the chamber change it is not. Since you are dealing with incomplete information here . I would suggest you do your own load testing to find your accuracy nodes and not try to take a short cut that may end in tears. The COAL I listed was it the bullet tip to base of the cartridge case measurement. Load up a dummy round to the 3.150 COAL then measure the round with a comparator to see what the CBTO is and compare it to your information if you want to see if its close , short, long to your 2.332. But if it was me. I would make a dummy round to the lands , re-find the seating depth sweet spot using the "VLDS, making them shoot" found in the TECH TALK section on our website at the lowest powder charge listed. Then work the load back up slowly checking for pressure signs and accuracy as you increase the powder charge till you find your velocity accuracy node. Sometimes its safer to just start all over.

I was thinking of doing this just as an exercise to see if I arrive at the same specs as he did. I know for a fact he developed his load after the chamber was redone. He weighs each piece of brass, measures each bullet's weight and length of bearing surface, etc etc. I would trust his work a lot more than my own, as I have never done this before. He has a lot of experience with it.

So by saying the data MAY be valid, are you also saying that with the re-chambering a load of 46.5gn would be safe? If I start doing a test, I'd like to know where my upper powder limit actually is.

 

[barefooter56]

I was thinking of doing this just as an exercise to see if I arrive at the same specs as he did. I know for a fact he developed his load after the chamber was redone. He weighs each piece of brass, measures each bullet's weight and length of bearing surface, etc etc. I would trust his work a lot more than my own, as I have never done this before. He has a lot of experience with it.

So by saying the data MAY be valid, are you also saying that with the re-chambering a load of 46.5gn would be safe? If I start doing a test, I'd like to know where my upper powder limit actually is.

SigSavage,
Your data "MAY"be valid. BUT do yourself a favor and start at the 41.5 grain charge and work up. Never ASSUME in this game. More often than not it usually ends in tears. No short cuts.
Take care

 

[SigSavage]

SigSavage,
Your data "MAY"be valid. BUT do yourself a favor and start at the 41.5 grain charge and work up. Never ASSUME in this game. More often than not it usually ends in tears. No short cuts.
Take care

K thanks. Just wanted to make sure I could safely get above your "max" charge if it goes there. I know people have said the 6.5x55 cartridge is generally underrated and can go beyond what most powder companies publish as "max" data. I don't want to be the one testing it though.