Long range load development at 100 yards.

[savageshooter86]

Just wandering how 1 velocity out of each group of 3 helps someone? Wouldn't it have been better to log each shot velocity of a charge weight and put that on the target. And then we could see the ES/avg per group. The one shot he recorded velocity for could have been the low of the ES for one group, or the high for another group, and the middle for the next group?

Or did I miss the point here?

 

[Steve Blair]

Here is my AIAE with Benchmark 6.5x47L barrel. Sierra 123 with Varget, 100 yards. last 2 groups the primer center started protruding but no blown primers, no other pressure signs, easy bolt lift. From what I have read the AI bolt tends to do this with small primers.

[br]
Primer extrusion as you describe is the result of a large firing pin hole. It is commonly corrected by bushing the bolt face and modifying or replacing the large diameter firing pin. I don't think I would do that with your AI bolt but is the most common approach. [br]
Sometimes, a hard cup primer like CCI 450 or Russian SRM (KVB-5.56M) will fix the problem. Worth noting is that these two primers are not reliable for detecting pressure.

 

[dieselten]

Just wandering how 1 velocity out of each group of 3 helps someone? Wouldn't it have been better to log each shot velocity of a charge weight and put that on the target. And then we could see the ES/avg per group. The one shot he recorded velocity for could have been the low of the ES for one group, or the high for another group, and the middle for the next group?

Or did I miss the point here?

You are correct. One velocity is pretty meaningless except that it lets me know the approximate velocity I am working with. I can test larger samples later. I use a Magneto speed that attches to the barrel so it is useless for grouping.

 

[dieselten]

Here is my AIAE with Benchmark 6.5x47L barrel. Sierra 123 with Varget, 100 yards. last 2 groups the primer center started protruding but no blown primers, no other pressure signs, easy bolt lift. From what I have read the AI bolt tends to do this with small primers.

[br]
Primer extrusion as you describe is the result of a large firing pin hole. It is commonly corrected by bushing the bolt face and modifying or replacing the large diameter firing pin. I don't think I would do that with your AI bolt but is the most common approach. [br]
Sometimes, a hard cup primer like CCI 450 or Russian SRM (KVB-5.56M) will fix the problem. Worth noting is that these two primers are not reliable for detecting pressure.

Thank you for the info, that is what my research had told me. I might experiment with harder primers or just stay at the lower node, depending on component availability.

 

[dieselten]

Here is my AIAE with Benchmark 6.5x47L barrel. Sierra 123 with Varget, 100 yards. last 2 groups the primer center started protruding but no blown primers, no other pressure signs, easy bolt lift. From what I have read the AI bolt tends to do this with small primers. I did chrono 1 round of some of the loads. These were the first 30 rounds through a brand new barrel, 8 rounds to sight in before starting this test. First group is 4 shots (cause it was stringing so bad I threw the last one in), the rest are 3.

What is your read?

Judging by your target, your rifle is very accurate, as most of the groups look good.

I would try 37.3 gr., since it's between 37.0 and 37.5, which both shot well. Also would be tempted to try 36.3 for the same reason, but I would try the faster node first. Good luck and post results after you do seating depth testing in .003" increments.

Thanks Erik

I was a little confused in that my nodes only seemed to span .5 grains of powder while most others spanned 1.0 grains.

I will test at 37.3 for seating depth and report back

 

[BoydAllen]

On cratering, if the primers hold, I would not worry much. I had a factory .222 in which I shot warm to hot loads, all of the primers were cratered, and none ever pierced. Hot loads can back up the pin to the point that the radius at the edge of the tip is in the hole, leaving a place for primer material to go under high pressure. A stronger spring and a little reshaping of the tip may help, so that the pin does not back up as much, and the radius does not extend as far back from the end of the pin. Of course, having the hole bushed will probably solve the problem. Just remember that some make the bushing long enough so that the tip does not come out of the hole, and others do not. Greg Tannel does.

 

[Steve Blair]

Of course, having the hole bushed will probably solve the problem. Just remember that some make the bushing long enough so that the tip does not come out of the hole, and others do not. Greg Tannel does.

[br]
+1 Greg did all my bolts that needed bushing. Quick service, correct and reasonably priced. [br]
http://www.gretanrifles.com/

 

[Chuckhunter]

Erik, here are my 100yd. groups from this morning. It's a 6MM Dasher shooting 105 Berger Hybrids Molyed, with CCI-450 Primers, Lapua Brass. All bullets jumping .020. There are six groups starting at 31.0Gr's of H-4895 and going up in .3 Gr. increments and ending with 32.5Gr's of H-4895. Could you please tell me what node you would settle on as this is new to me. Thank

 

[Erik Cortina]

Chuckhunter, looks like 31.3 gr is in the middle of a node. But it also appears that 31.9 and 32.2 are another node. I would also try 32.0 gr to see how it does.

Work on 31.3 first and work on seating depth moving .003" at a time.

 

[Chuckhunter]

Erik, thanks for the quick response. I was also thinking along the same line. I will definitely try 32.0Gr's and I think I'm pretty close on seating depth, a few minor tweaks and I should be good to go. Thanks again.

 

[jsthntn247]

I would load 31.3 and 32.0 at different seating depths as mentioned, but shoot you groups further out (300) if possible. Not going to be able to tell much if all your groups are in the .1's.

 

[Erik Cortina]

I would load 31.3 and 32.0 at different seating depths as mentioned, but shoot you groups further out (300) if possible. Not going to be able to tell much if all your groups are in the .1's.

Read the thread title.

 

[savageshooter86]

I would do like Erik suggested. 31.3 looks great. I would do a few seating depths and re-shoot 31.0, 31.3, and 31.6 gr. I would find the seating depth that has least vertical in the groups and make sure it is a node again. 31.3 looks perfect, but 31.0 and 31.6 has a good bit of vertical. If I had a rifle that shot this accurate, the above would be based on Tony B's method he describes in his book

Great shooting 8)

 

[jsthntn247]

I would load 31.3 and 32.0 at different seating depths as mentioned, but shoot you groups further out (300) if possible. Not going to be able to tell much if all your groups are in the .1's.

Read the thread title.

I did, I've posted how this worked for me on the last page. I also believe that it has it's limits. If he shoots the next test as you instructed and he get's all one ragged hole groups (which it appears the gun is capable of), what does that tell him? He learns nothing. But if he were to shoot those same loads at 300+, he could get some valuable info on what seating depth works for that charge.

 

[Erik Cortina]

I would load 31.3 and 32.0 at different seating depths as mentioned, but shoot you groups further out (300) if possible. Not going to be able to tell much if all your groups are in the .1's.

Read the thread title.

I did, I've posted how this worked for me on the last page. I also believe that it has it's limits. If he shoots the next test as you instructed and he get's all one ragged hole groups (which it appears the gun is capable of), what does that tell him? He learns nothing. But if he were to shoot those same loads at 300+, he could get some valuable info on what seating depth works for that charge.

:-X

 

[jsthntn247]

I would load 31.3 and 32.0 at different seating depths as mentioned, but shoot you groups further out (300) if possible. Not going to be able to tell much if all your groups are in the .1's.

Read the thread title.

I did, I've posted how this worked for me on the last page. I also believe that it has it's limits. If he shoots the next test as you instructed and he get's all one ragged hole groups (which it appears the gun is capable of), what does that tell him? He learns nothing. But if he were to shoot those same loads at 300+, he could get some valuable info on what seating depth works for that charge.

:-X

Ok Erik, this is what I AM going to do. I HAVE tested a load at 100 yards (one hole) and KNOW that it IS a good load at 300 also. I have NOT played with the seating depth though. So I AM going to vary the seating depth by .003 as you say is best and shoot the loads at 100 and 300. I will first post the 100 yard target and let you decide which load you THINK will be best at 300. Then I will post the 300 yard pics shot with the same loads at varying seating depth's on the same day. Going to put you on the spot and we can both see at the same time if 100 yard testing has it's limits or not. Sound peachy? ;D

 

[Erik Cortina]

I would load 31.3 and 32.0 at different seating depths as mentioned, but shoot you groups further out (300) if possible. Not going to be able to tell much if all your groups are in the .1's.

Read the thread title.

I did, I've posted how this worked for me on the last page. I also believe that it has it's limits. If he shoots the next test as you instructed and he get's all one ragged hole groups (which it appears the gun is capable of), what does that tell him? He learns nothing. But if he were to shoot those same loads at 300+, he could get some valuable info on what seating depth works for that charge.

:-X

Ok Erik, this is what I AM going to do. I HAVE tested a load at 100 yards (one hole) and KNOW that it IS a good load at 300 also. I have NOT played with the seating depth though. So I AM going to vary the seating depth by .003 as you say is best and shoot the loads at 100 and 300. I will first post the 100 yard target and let you decide which load you THINK will be best at 300. Then I will post the 300 yard pics shot with the same loads at varying seating depth's on the same day. Going to put you on the spot and we can both see at the same time if 100 yard testing has it's limits or not. Sound peachy? ;D

Sound good, also give me chronograph readings from a good reliable chronograph such as an Ohler 35 or PVM-21.

 

[Ed333]

Newbie question, trying to follow and apply this thread (because of powder and bullet availability, I have had to shift to a new powder and new bullets). I was pushing the envelope a bit (slightly above VV website or Berger manual max) with powder load of N540 in my 6BR, with 105 Berger VLD Hunting , jammed .010", and when I examined the cases after extraction, I have a burr on the primer, enough to catch my finger tip as I lightly go across the cartridge base. Too much powder?
This thread's testing is tough to apply with consistency

 

[Erik Cortina]

Newbie question, trying to follow and apply this thread (because of powder and bullet availability, I have had to shift to a new powder and new bullets). I was pushing the envelope a bit (slightly above VV website or Berger manual max) with powder load of N540 in my 6BR, with 105 Berger VLD Hunting , jammed .010", and when I examined the cases after extraction, I have a burr on the primer, enough to catch my finger tip as I lightly go across the cartridge base. Too much powder?
This thread's testing is tough to apply with consistency

Depends, most factory rifles have the firing pin hole too big and will crater primers easily. Did you get hard bolt lift or any other signs of pressure?

 

[BoydAllen]

Just out of curiosity, what sort of rifle, rest, bags, flags, range conditions?