# Help me figure something out



## goatchze (Aug 1, 2006)

So I've made a few posts here about some new loads I'm playing around with. I'll have to say, it's a lot of fun experimenting. Although we've been reloading for years, we've always just loaded the same bullet, with the same powder, the same way, because that's how Pawpaw did. Until I bought this 260 a few years ago, I never thought much about trying different things. Now I think about it a lot!

As some of you know, I started out looking for a single bullet that could do everything for me. What I realized in this search is that I had lost my way a bit; the whole reason for picking the 260 was because of the options I could have. Why try to find a single bullet to settle on? So now I've got 5, ranging from 85gr to 156gr. Here's what I loaded up this weekend.










I loaded each to the book "max load" and went out and shot some to see how they did. I fired a group of 3 of each round, here are the results.










Velocites were very consistent, < 0.75% difference between the 3 of each group. All were about 100fps slower than predicted, but I'm shooting the shorter barrel model 7. Might be expected.

What I wasn't expecting, however, was the left to right differences that I saw? Now, I understand that my scope isn't sighted in properly and is shooting low. And the wind was blowing a bit, though not bad. Still, I would have expected something more consistent? There's a 6" difference between two of the groups? I would expect the wind to affect each round differently, but not that differently?

The difference in height makes sense. Below is a graph of "calculated" trajectory.










Of coures, this graph assumes the scope is zeroed at 150yds for each round, but I would expect that if I was zeroed for a single round, the pattern would be the same (95gr VMax behing the highest and the Norma being the lowest). This is exactly what I see on the target.

So what are your suggestions? What was going on?


----------



## CoastalOutfitters (Aug 20, 2004)

i have rarely got the best group off the "max" load in the book, usually it is about 2 grs back on big cases.

the horizontal variance is a real head scratcher and I highly doubt due to wind with that cal., also does not look like a hot barrel spread............dunno

try an old school sierra spitzer and back it off just a touch from max. 

maybe in the 125-130 gr. range


----------



## Ernest (May 21, 2004)

You have to work up to the load that is right for your gun. I'm not saying you always have to start with the absolute min, but start low and work up. Sometimes the accuracy load is at the top. More often, you will find a couple accuracy "nodes." A small range of charges where the gun shoots great. There is typically a low node and then perhaps a higher velocity node. 

Until you find one of these nodes for each bullet, trying to read three shot groups and figure out why you are seeing horizonal spread between different bullets is pizzing in the wind. Waste of time.


----------



## davidb (May 10, 2006)

Barrel vibration is different for each load and even for the same bullet with different powders. The point of impact will change with the changes in barrel harmonics (vibration). 

It's kind of like when Elmer Fudd fires one off with his blunder buss and the barrel swells up and wobbles then spits the bullet out. The barrel wobbles differently with different loads.

Never start with a max load, as you work up you will see some differences in accuracy and point of impact. Not only safer but will get you closer to an accurate load quicker.

Enjoy.


----------



## goatchze (Aug 1, 2006)

Thanks guys, I guess I was just surprised at how far of a spread there was between groups but not within groups, and I couldn't understand why. I'm going to go through different combinations of powder and charges to see what's best for each round. I never planned or figured that the max load would be the best choice; just what I used Saturday to see what the velocities were like.


----------



## coogerpop (Sep 3, 2009)

1.Pick a bullet.
2.Start 3-4 gr below max and build up 3-4 cases with each weight.
3. Fire for grouping.
4. take best one and change primers...
5.Take best.
You are pretty close to the best of this combo.

Take the same bullet and change powder...then do the above steps...


take the best 

This is the reason most old time reloaders have numerous cans of powder...try different combos..and seating depths ...and primers but develop a standard to measure them against ...and keep good records...


----------



## Pocketfisherman (May 30, 2005)

One of the ballistic factors is the gyroscopic lateral force caused by the spin of a bullet pulling it to the right off the bore line. If you put your finger on a spinning gyroscope and push it, it will deviate it's path 90 degrees from the direction the push came from. With your bullet spinning, gravity is the finger pushing that little gyroscope down and the deviation will be to the right.

The strength of that factor depends on the RPM of the bullet which is a function of the velocity it leaves the barrel and the barrel's twist weight. This is one of the reasons Snipers work up a table for each load and bullet weight. It is not just the vertical stringing that is going to vary, but horizontal as well. This is where having a scope with turrets you can zero out comes in handy because you can establish a rifle baseline, and then log the V and H variance for each load and distance.


----------



## Pocketfisherman (May 30, 2005)

After doing all this below, then start varing the seating length to dial it in the last little bit. Having a comparator really helps. If you don't, put a bullet in an empty neck sized case leaving it in the case just enough to hold it secure, but not fully seated, and close the bolt on it. The bullet will get pushed into the case with zero headspace and resting on the lands of the bore. Seat it in a couple hundredths from there.



coogerpop said:


> 1.Pick a bullet.
> 2.Start 3-4 gr below max and build up 3-4 cases with each weight.
> 3. Fire for grouping.
> 4. take best one and change primers...
> ...


----------



## goatchze (Aug 1, 2006)

Pocket,

Thanks for the explanation, that makes sense. It wasn't something I had considered. I did as you said and set the bullet seat back 0.020" on the bullets already fired. I double checked it using a few marked bullets set at various lenghths. I'll probably leave it like this to try and eliminate as many variables as possible, perhaps I'll change it later.

Cooger,

Thanks, that's what I plan on doing. Will be a while until I can get back to shooting,(I'm leaving on a business trip this weekend) but I'll post up results if anyone is interested. I'm going to start with the VMax and change only the grains of powder in the case, holding everything else as constant as possible. Hopefully I'll see the two "nodes" that Ernest talked about. Once I find about where these are, I'll narrow my range of powder over each node (or at least the more appropriate of the two if I find two) and see if I can tune it more. I'll probably then do the same for the other bullets, keeping everything constant as before, then compare where the "nodes" are (if I find them) for each bullet. Later I'll try different powders.

Sounds like I've got some loading and shooting to do!


----------



## CHARLIE (Jun 2, 2004)

I noticed Vmax in the mix there. What you plan on shootin with a Vmax? Not deer I hope.

Charlie


----------



## goatchze (Aug 1, 2006)

Nah. I use the 129 SST on deer. Works quite well. I may consider the 156gr Norma Oryx for deer this fall; we'll see.

I shot some hogs with the VMax...didn't work out too well. The 85gr HP didn't seem to have much issue with pigs, but the VMax just exploded with no penetration. Lesson learned.

I guess I should have labeled the first picture. From left to right are:

85gr Sierra HP
95gr Hornady VMax
110gr Barnes Banded Solid
129gr Hornady SST
156gr Norma Oryx


----------



## 27contender (Dec 22, 2008)

Ive seen horizontal spread due to powder type and thus velocity changes. Everything else was the same. Guns do not like certain velocities. Problem is they are like women, everyone of them likes a different speed even when they are the same caliber.

Hope that helps

Rick


----------



## CoastalOutfitters (Aug 20, 2004)

looks like the round was designed around the 120 gr and 140 gr bullets with 140 being the go-to


----------



## davidb (May 10, 2006)

One way I develop loads is to pick your main bullet choice tune that load and then the pick a secondary load and try to tune it to the same point of impact as numero uno. 

This will usually work with a well balanced cartridge like the 260. Other finicky cartridges you could burn out a barrel before getting two compatible loads.


----------



## THE JAMMER (Aug 1, 2005)

That's a new one on me. How do you "tune a load to have the same poi" as a previously developed load?

I've always tried to develop the most accurate I could for one bullet, and then did the same for another bullet. If they happened to have a similar poi, I counted myself lucky.

THE JAMMER



davidb said:


> One way I develop loads is to pick your main bullet choice tune that load and then the pick a secondary load and try to tune it to the same point of impact as numero uno.
> 
> This will usually work with a well balanced cartridge like the 260. Other finicky cartridges you could burn out a barrel before getting two compatible loads.


----------



## Screeminreel (Jun 2, 2004)

THE JAMMER said:


> That's a new one on me. How do you "tune a load to have the same poi" as a previously developed load?
> 
> I've always tried to develop the most accurate I could for one bullet, and then did the same for another bullet. If they happened to have a similar poi, I counted myself lucky.
> 
> THE JAMMER


It takes a bit of tweaking, but it can be done. For my .243, 25-06 and .270 I had loads which I could easily swap from one to the other with no real measure of change out to 300yds. They all used about the same charge but different bullets. For the .243 I had a 90gr Barnes X, a 95gr Partition and Ballistic Tip which all hit within a 1" group out to 200yds. They would group together individually but all keep within the same aggregate. Same for the 25, it used a 115gr Barnes X, and the 115gr Partition, or in 100gr the Partition, the BT and the Barnes X. For the .270 it was a 130gr Solid Base a 140gr BT, and a 110gr Branes X.


----------



## Ernest (May 21, 2004)

Agree with Jammer - the difference b/w a 85 or 90 and a 140 or 156 is freakin huge. 

Sure, you can potentially figure out a range - be it 29.5 yards or 151 yards - where the flight paths intersect, but to what end? There are flying very different paths unless you load the 156 super hot and the 85 or 90 real freakin weak. Even then, the BC is different. 

Load each bullet to an accuracy node. Dope the loads in the field. Write down the dope. Hold over, hold to the side, or work the clicks on the scope. This approach is far, far, far easier, and most importantly, it works. Tried and true. *****, even use a little ink pen to mark the scope - red line is for the 90 grain load at 200. Blue line is for the 129 at 200, and so on.


----------



## goatchze (Aug 1, 2006)

Ernest said:


> Agree with Jammer - the difference b/w a 85 or 90 and a 140 or 156 is freakin huge.
> 
> Sure, you can potentially figure out a range - be it 29.5 yards or 151 yards - where the flight paths intersect, but to what end? There are flying very different paths unless you load the 156 super hot and the 85 or 90 real freakin weak. Even then, the BC is different.
> 
> Load each bullet to an accuracy node. Dope the loads in the field. Write down the dope. Hold over, hold to the side, or work the clicks on the scope. This approach is far, far, far easier, and most importantly, it works. Tried and true. *****, even use a little ink pen to mark the scope - red line is for the 90 grain load at 200. Blue line is for the 129 at 200, and so on.


You're right, the difference between the lightest bullet and the heaviest is huge; it's why I think this will be a fun gun to play around with. It's also why I chose the caliber; it's effectively a varmint rifle and a deer rifle in one, depending on the bullet fired.

It would be great if I could get them all on center line, but I don't think that's going to be my plan. I'm going to try and find the right load for each which tightens up the groups. Then I'll make the same graph as I put up on this thread for each of the 5 loads. I'll pick the round that is closest to the center and zero my scope with that.

That's what I'm thinking, but we'll see how it all pans out. I plan to be pretty thorough and I'll keep everyone posted.


----------



## THE JAMMER (Aug 1, 2005)

Regarding which load you zero your rifle to: I zero mine to the load I plan on shooting the most in that gun. I then shoot the other loads I will be shooting in that gun and develop a dope sheet for that rifle such as:

168 smk dead on
150 fmj 3 clicks up and 6 right
130 xxx 8 clicks up and 3 right

Then you can laminate that little card and tape it to your stock or whatever.

By the way I am chomping at the bit to shoot my M1A with my new Troy industries MCS- Modular Chassis System. Unfortunately I had rOtator cuff surgery 9 days ago, and will be in a sling for the next 2 1/2 weeks. Really tough looking at that thing just sitting there screaming " shoot me," and not even being able to pick it up, much less shoot it.

THE "GROUNDED" JAMMER

etc.


goatchze said:


> You're right, the difference between the lightest bullet and the heaviest is huge; it's why I think this will be a fun gun to play around with. It's also why I chose the caliber; it's effectively a varmint rifle and a deer rifle in one, depending on the bullet fired.
> 
> It would be great if I could get them all on center line, but I don't think that's going to be my plan. I'm going to try and find the right load for each which tightens up the groups. Then I'll make the same graph as I put up on this thread for each of the 5 loads. I'll pick the round that is closest to the center and zero my scope with that.
> 
> That's what I'm thinking, but we'll see how it all pans out. I plan to be pretty thorough and I'll keep everyone posted.


----------



## Africanut (Jan 15, 2008)

Have by far my best groups of a little >1/4 with Sierra 142 SMK's over 48.5 grs of VV560 in my .260 Runs them out at 2850 on a 25 inch Brux. Don't let anybody fool you the SMK's are awesome deer bullets in the "lesser" calibers. Need a 8.5 twist or quicker to run this one though--good luck...


----------

