Reloading impact question ❓

[Diver43]

OK, to make a long story short. Loading .308 167 gr ELD-M bullets over 40 grains, 41 grains and 42 grains of powder. 40 grains impact wad approx 5 inches high. 41 grains 3 inches and 42 grains was an inch high.

I am not an experienced reloader nor a roçket scientist. But, my thinking says it should have been the opposite

Can anyone make me a little smarter ?-

[PFD45]

Might be due to higher velocity = lower dwell time for the bullet in the barrel.

The bullet gets out of the barrel before it rises more.

Or sun spots?

[Wambli Ska]

Harmonics, I’ll call you. Can’t type that much…

[GrapeApe]

Harmonics, I’ll call you. Can’t type that much…

Yep, it takes something like 0.01" or 0.001" (I forget which) of movement at the muzzle to move the POI 1" @ 100 yards. and if you get a chance to see a CF rifle being shot on a super slow motion camera, the muzzle whips around like you wouldn't believe. Where the muzzle is when the bullet leaves is a HUGE thing

[GrapeApe]

https://youtu.be/_9ULBtsnkR0?si=bmM6SIqI9sSqqOV9

[Diver43]

Amazing. I have heard of barrel harmonics, but thought it was vibration, not actual movement

[Diver43]

Amazing. I have heard of barrel harmonics, but thought it was vibration, not actual movement

[Linefinder]

Simple answer....the longer your bullet stays in the barrel, the higher it's going to hit.

Mike

[Freezer]

This may sound overly simple but work your load up one grain at a time. When you find the most accurate, change it by one quarter and a half grain up and down till you find the most accurate load. Use the load charts to determine the trajectory and be happy.

If you really want a good book on the subject, get "Understanding Firearms Ballistics". It is written in three levels, so everyone can understand it. For the novice it has simple explanations, and for the expert and mathematician it has the formulas.

Needless to say, I failed math but was engrossed with the book. I don't have it anymore, but now that I'm reloading and shooting more, I may have to find it on kindle.

[GrapeApe]

Yep Robert A. Rinker's book is a GREAT resource

[Diver43]

This may sound overly simple but work your load up one grain at a time. When you find the most accurate, change it by one quarter and a half grain up and down till you find the most accurate load. Use the load charts to determine the trajectory and be happy.

If you really want a good book on the subject, get "Understanding Firearms Ballistics". It is written in three levels, so everyone can understand it. For the novice it has simple explanations, and for the expert and mathematician it has the formulas.

Needless to say, I failed math but was engrossed with the book. I don't have it anymore, but now that I'm reloading and shooting more, I may have to find it on kindle.

I did work my way up to max load. Each step closed the group and brought it closer to POA.

[GrapeApe]

POA is a variable, and a load hitting close to the existing POA is fairly irrelevant since you can adjust POA for the chosen load.

In my 6.5 Grendel, EVERY load I've tried with Nosler Ballistic tips shoots considerably left (3-4") of the established POA of both Hornady Amaxes and Speer Gold Dots

[Diver43]

POA is a variable, and a load hitting close to the existing POA is fairly irrelevant since you can adjust POA for the chosen load.

In my 6.5 Grendel, EVERY load I've tried with Nosler Ballistic tips shoots considerably left (3-4") of the established POA of both Hornady Amaxes and Speer Gold Dots

Understand, just an observation that with each increase of powder, the group closed up and moved closer to POA. The target looked like I was making scope adjustments. I wish I had gotten a photo, but it was a public range and I didn't want to wait for a ceasefire

[Bigslug]

You witness this phenomenon a lot with light loads in magnum-rated revolvers. The gun has a high bore axis which causes them to pivot on their axis of recoil-rotation to a greater degree. The gun starts recoiling as soon as the bullet starts moving forward, and a slower bullet takes longer to get out of the gun - ergo, the muzzle has climbed more off the POA at the point the bullet exits with the slower load.

This will likewise be more pronounced with something like a '94 Winchester or other low stock comb that was designed for iron sights than it will with something like an inline-recoiling AR-15, or a good straight-comb, scope-ready bolt gun like a Ruger M77.

[PFD45]

Well I'll be...

[jwv2023]

where did the 2nd and 3rd shot hit at each of those loads? Whichever was the best group, load that. Then sight in for the range your going to shoot. Accuracy is the only thing that matters as a handloader. Don't get excited by velocity, only get excited about how close you can get to the point of aim.

[Diver43]

where did the 2nd and 3rd shot hit at each of those loads? Whichever was the best group, load that. Then sight in for the range your going to shoot. Accuracy is the only thing that matters as a handloader. Don't get excited by velocity, only get excited about how close you can get to the point of aim.

With each increase in powder, the group closed and also got closer to POA. I stopped at book max