Finding the node

[TackDriver284]

Headed off to the range with the .308 and forgot the damn chronograph, so did a 3 round group test with the MR-2000 and 185 Juggernauts in the .308 I never used MR-2000 and wanted to give it a try. Charges are in .3 increments as in order from left to right, 45.1, 45.4, 45.7, 46.0, 46.3, 46.6, 43.9, and 47.2 grains. Little wind from left to right at 5 to 8 mph and test is @ 100 yards. Should have done 200 but wind was acting a little weird. Velocity is unknown, but sure gives a sharper recoil than the 168 / 175's.
Opinions on a node? I was choosing # 3, 4 and 5 and try again @ 200 or 300. What say you?

 

[drakehammer]

Headed off to the range with the .308 and forgot the damn chronograph, so did a 3 round group test with the MR-2000 and 185 Juggernauts in the .308 I never used MR-2000 and wanted to give it a try. Charges are in .3 increments as in order from left to right, 45.1, 45.4, 45.7, 46.0, 46.3, 46.6, 43.9, and 47.2 grains. Little wind from left to right at 5 to 8 mph and test is @ 100 yards. Should have done 200 but wind was acting a little weird. Velocity is unknown, but sure gives a sharper recoil than the 168 / 175's.
Opinions on a node? I was choosing # 3, 4 and 5 and try again @ 200 or 300. What say you?

Luxury problems. Lol. I’d repeat 1-7 and go from there. Theres just not much difference yet...

You narrowed it down. Load’em back up and move to 200 with chrono if you like.


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[TackDriver284]

I agree Drake, need to take my chrono and try again. Actually forgot to add that this was virgin brass and just broke open a box of Lapuas.

 

[mjcmichigan]

I like 4-5-6 too. Pretty tight. 3 looked a little like 2. Maybe repeat but add 0.1gn to all. Might make the node more apparent


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[TackDriver284]

I like 4-5-6 too. Pretty tight. 3 looked a little like 2. Maybe repeat but add 0.1gn to all. Might make the node more apparent


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Yes, I thought the same, I may have pulled on # 6.

 

[Elkman]

I should probably know but what rifle are you shooting, and what is your final goal? Targets, hunting, long range etc. Your shooting skills are very good, for that much time on the bench. Save your self some time reshoot number 5 if it repeats it's self you are done, you can't get much smaller.

 

[TackDriver284]

I should probably know but what rifle are you shooting, and what is your final goal? Targets, hunting, long range etc. Your shooting skills are very good, for that much time on the bench. Save your self some time reshoot number 5 if it repeats it's self you are done, you can't get much smaller.

Actually long range targets with the .308 GAP Crusader with 26 inch barrel.

 

[drakehammer]

I should probably know but what rifle are you shooting, and what is your final goal? Targets, hunting, long range etc. Your shooting skills are very good, for that much time on the bench. Save your self some time reshoot number 5 if it repeats it's self you are done, you can't get much smaller.

Actually long range targets with the .308 GAP Crusader with 26 inch barrel.

If long range paper is your goal, you really don’t know much of anything yet. Pick your favorite groups and move out to your anticipated distance and work at that range with that load.

I have 3 6BR/6BRX 600 yard benchrest barrels and none have never been shot at anything less than 600. Thats where it counts.


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[hunter24605]

Nice shooting,Pard! I believe I'd load #5 again, along with .1 above and .1 below And step out to 200 and shoot those three charges.

 

[TackDriver284]

One thing that bugs me is point of impact. As you know more powder equals more velocity, and more velocity equals higher point of impact, so if you look along the point of impact from first 3 round group to the last group, you can see the slant from left to right as higher from first 3 round groups and lower at the last 3 round group. Why would that be? :?:

 

[hunter24605]

One thing that bugs me is point of impact. As you know more powder equals more velocity, and more velocity equals higher point of impact, so if you look along the point of impact from first 3 round group to the last group, you can see the slant from left to right as higher from first 3 round groups and lower at the last 3 round group. Why would that be? :?:

Just spit-balling here, but maybe higher velocity = flatter trajectory; still under line of sight @ 100 yards?

 

[salmonchaser]

Had an old Palma shooter tell me that situation was caused by barrel harmonics. But I really have no idea, just popped into my head, an ancient memory no doubt spurred on by reading Dr. Mike and Aprils memories.


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[Elkman]

The bullet is rotating as we all know, perhaps the increased velocity is not allowing the bullet to fully stabilize at that distance so the bullet is wobbling differently at each change. It will be intereresting to see if it goes away at longer range.

 

[RaySendero]

.....
.
Opinions on a node? I was choosing # 3, 4 and 5 and try again @ 200 or 300. What say you?

I like #s 5 and 6.

 

[Dwh7271]

I'd think barrel harmonics as mentioned before. Barrels move. :grin:

 

[Elkman]

I like 5 for sure, I will be excited to see how they shake out. Most of my shooting is done at 300 yards, because gives more honest load evaluation, and my hunting rifles are all zeroed at 300.

 

[ozarkpugs]

Ok I'm very confused by some of the wondering , for lack of a better word , about why some loads are higher with less velocity . Here is why I do ladders to find three or so loads that are at the right place within the travel of vibration to put the bullets close to the same place. Barrels whip and bend as vibrations travel up and back down them . Why is this important ? because if 35.0 35.2 35.4 are on same plane I can load 35.2 and temp changing VELOCITY will not effect my poa . 34.8 may have the bullet exiting just as the vibration gets to the end of the barrel . To understand this more easily hold a 3 ft pipe in front of you and have a friend strike it with a hammer and you will feel vibrations like they are strong and weak running up and down your barrel you want the bullet to exit when the vibration is strong at your hand ( receiver) not the other end ( muzzle ) .

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[mjcmichigan]

Ok I'm very confused by some of the wondering , for lack of a better word , about why some loads are higher with less velocity . Here is why I do ladders to find three or so loads that are at the right place within the travel of vibration to put the bullets close to the same place. Barrels whip and bend as vibrations travel up and back down them . Why is this important ? because if 35.0 35.2 35.4 are on same plane I can load 35.2 and temp changing VELOCITY will not effect my poa . 34.8 may have the bullet exiting just as the vibration gets to the end of the barrel . To understand this more easily hold a 3 ft pipe in front of you and have a friend strike it with a hammer and you will feel vibrations like they are strong and weak running up and down your barrel you want the bullet to exit when the vibration is strong at your hand ( receiver) not the other end ( muzzle ) .

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You need the chrono numbers. A node is where velocity is pretty stable. So if you are off by 0.03, it doesn’t open the group.
If you are in a zone where each 0.1 adds 30 fps,it’s really hard to get that consistent.

In this example, the evidence suggest of you load between 3 and 6, you’ll hit the same basic spot.


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[Bbear]

I'd load 3-6 and bring the chrony and shoot at 200

 

[SJB358]

I'd load 3-6 and bring the chrony and shoot at 200

Same here.