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Topic: Nodes and Magnetospeed (Read 1117 times) previous topic - next topic

Nodes and Magnetospeed

I'm wondering if chrongraphing during load development with a Magnetospeed attached to the barrel might change the rifle's natural nodes?

I believe hanging anything off a barrel temporarily might change the harmonics, what I'm not sure of is what barrel harmonics has to do with nodes.

Any thoughts on the matter?
Chris

Re: Nodes and Magnetospeed

Reply #1
It will change the point of impact usually up in my experience. It will also act as a tuner and make some loads group tighter than without.

The actual node in terms of a velocity node, ES & SD stays constant. This is what the magnetospeed should be used for. Identify the charge weight that gives the best ES & SD over a .5 -1 grain spread then take the magnetospeed off and center the charge and find the optimal seating depth to tune the load.  
Dave

Re: Nodes and Magnetospeed

Reply #2
The MS provides a very accurate assessment of MV but it does influence POI. That influence seems to be more evident when the weight of the tool is affecting the harmonics of a long slender barrel versus a short rigid barrel.  Bullet velocity for every round being used to run a ladder test or and OCW is NOT required to find nodes along a sequence of increasing charge weights.

If you are using an optic or radar type chrono you have the luxury of seeing the velocity of every round during your testing. Using proper interpretation of the testing method you choose, find your nodes and then go back to those charge weights with the MS attached and record the corresponding velocity.

Re: Nodes and Magnetospeed

Reply #3
The MS provides a very accurate assessment of MV but it does influence POI. That influence seems to be more evident when the weight of the tool is affecting the harmonics of a long slender barrel versus a short rigid barrel. 

My experience as well. My heavy barreled rifles print about 2" high at 100 while my lighter barreled hunting rifles come in about 7" high @ 100 yards.
Dave

Re: Nodes and Magnetospeed

Reply #4
The v3 doesn't affect POI on my 223 or 7mm08, but they're both straight profiles with 1.005" muzzle diameters.
Silence is golden. Duct tape is silver.
I have a lot of guns... There, I said it.

Re: Nodes and Magnetospeed

Reply #5
Bullet velocity for every round being used to run a ladder test or and OCW is NOT required to find nodes along a sequence of increasing charge weights.

I agree that knowing the velocity of every round in an OCW or ladder test may not be required to find nodes. That's why I believe these tests work well for great shooters who also have the hand loading equipment and skills to make great, consistent ammo. Then there are schlubs like me who are still working on developing both marksmanship skills and hand loading proficiency.

The problem I see with small sample set tests like OCW is how to interpret vertical spreads; did that shot go high or low because it had a few extra, or fewer 1/10 grains in it? Or did I pull the shot? Or maybe it's a true reflection of what that rifle does with that charge. In other words, there are things which may occur that could make any particular group invalid for overall test purposes. My thought is knowing the velocity of each round in a group may help to give me confidence that the group is valid for test purposes.
 
Back on the Magnetospeed, as long as it doesn't change the nodes, I guess it can't hurt to use it.
Chris

Re: Nodes and Magnetospeed

Reply #6
Bike, you and I, as well as most of our other shooters are on this forum to help ourselves learn how to overcome deficiencies we may have in reloading knowledge, methods of testing, shooting skill, etc, etc. If you have a camera, can download pictures to the forum, and learn from some constructive guidance, you are not going to need five more years of personal development to find nodes for your rifle. Anyone who tosses on a thread asking for OCW test interpretation, usually gets inundated with replies from folks who know what they are doing.

Because of the uncertainty of the affect of a MagnetoSpeed on any particular rifle, I would not do any node development tests with the unit attached to the barrel. I would only use it to find out what the velocity of my chosen node is. I would also use it to check velocities on any loads that I thought I might be seeing excessive pressure.

If you really just have to know where your velocities are, here is an idea. Select the range of charges you want to evaluate. Let’s say H4350 ranging from 40.7 thru 42.4 set at 0.3 grain increments. Load eight rounds of each charge. Start with a clean barrel and run a few fouling shots thru. Place your MS on and record the velocity from two rounds of each charge bottom to top watching for excessive pressure in the cases and correlating your observations with the recorded velocity. Remove the MS and run one OCW using three rounds from each charge weight. Repeat another OCW with the three remaining rounds of each charge weight on a second day of shooting to make sure your first OCW results are repeatable - this gives you confidence in your interpretation and helps to buffer any erroneous result created by a pulled shot or a slightly aberrant charge in any of the rounds you produced. Post pics while you are collecting your target data and you will see the benefit of this forum. 😊

We have had a lot of discussions recently about the pro and cons of the MagnetoSpeed versus the LabRadar. The fact that ALL of your shots during load development can be recorded while simultaneously printing the target, is a pro for LabRadar - but it’s NOT a requirement for successful acquisition of a node.

Re: Nodes and Magnetospeed

Reply #7
I like the plan you suggested Jerry, see, that's why you get paid the big bucks  :)

Thanks!
Chris

Re: Nodes and Magnetospeed

Reply #8
What Jerry said, I use a magnetospeed.  When I know I'm close to where I want to be, I'll load 4 or 5 rounds at each weight and shoot my test target with 3 rounds, then go back and put the M.S. on and fire 1-2 rounds left for the M.V.  I can usually see what kind of groups I'm getting with 3 rounds and the remaining 2 are very close in speed to see what I'm pushing them at. Not wasting a lot of time and rounds this way.

Re: Nodes and Magnetospeed

Reply #9
Thanks Ranger 188.

I'm usually pretty good at devising my version of how to do something, not sure why these OCW tests freeze me in my tracks.

I'm glad I have a place where I get an intervention  :))

Chris

Re: Nodes and Magnetospeed

Reply #10

http://forum.accurateshooter.com/threads/long-range-load-development-at-100-yards.3814361/

Here is a challenge to your commitment to learn how to develop a load😊. If someone here responds that they have read all 101 pages of this thread I will be impressed. If you are a newbie and do read and comprehend what’s in this exhaustive Accurate Shooter thread - you won’t be a newbie any more!

It’s of benefit because virtually every mistake that can be made in performing or interpreting an OWC comes to light in this discussion. I think the most common mistake made is the concept that you are looking for 2-3 successive groups along your escalating charge weight that produce tight groups. That is totally wrong!  Regardless of the group size, you are looking for 2-3 successive groups that print on the same region of the target. It’s so tempting to see a really good single group in your string and say wow - .250 MOA- ok that’s my node even though the groups on either side of it print on a different region of their targets. That approach will screw you up every time.

In this thread there are many posted target pictures with discussions of where the node lies. It’s good practice to help you learn how to read your own load development targets.

Some guys take exception to this thread because it’s focus is set at 100 yard development and they feel you don’t know what your load is really going to do at distance until you test it at least out to 300 yards. I agree with the extended yardage testing but it’s accurate and a lot easier to do the initial work up at 100 yards versus 300 yards.

Re: Nodes and Magnetospeed

Reply #11
I have read that entire thread and it did change the way I pursue load development.
Dave

Re: Nodes and Magnetospeed

Reply #12
The thread really is a challenge to get through- mainly because of some of the egotistical BS that you occasionally find on AS. It’s amazing to me how belligerent and narrow minded some people can be when they aren’t communicating face to face. The comradeship and open mindedness of the folks on this forum is impressive.

I mean think about it.... what other forum would put up with dadajack? 😂
Ummm, I going to pay for that statement!

Re: Nodes and Magnetospeed

Reply #13
bikemutt, one problem could be, your barrel isn't broke-in.  I find this to be a problem for me. I'll start trying to find a load to early on and then the barrel "speeds up a little" and I'll have to keep looking.  2. Your not in the best node.  Most good shooters on here agree that their is multiple nodes and their are good ones and better ones.  Meaning that some will have a wider velocity range than others.  Some days you can go to the range and shoot 1 hole groups and the next it's crap.  Once you can repeat your groups over multiple times, then you got a winner.  3 Keep everything consistent.  Even if it's not the group you want, you'll know thats not the one for you. 4  DON'T change more than one thing at a time.  Keep your targets and mark then with all the info on the load you used.
One last thing, if you barrel has lots of rounds on it, your "jump" might have change. You'll have to lengthen your load.

Yes my M.S. did change my P.O.I

Re: Nodes and Magnetospeed

Reply #14
The biggest challenge to learning from that thread now versus when it was new is there are a lot of good pictures that are no longer there.
And you are correct about the egos.
Dave