Ruger American 243 does not like eldx 100gr

[MaxxiD]

Loaded a bunch for a range day yesterday and I could barely keep them on paper. Turned back to my federal power shok 100gr and they were lights out.

Anyone have this experience or know what the problem might be?

Thinking about trying 100gr interlocks next

[FishOutOfWater]

6mm Hornady ELD-X doesn't come in 100gr, but you know that... They're 103gr.

And factory barrels usually don't have the twist-rates to stabilize heavier bullets, but some do shoot them well.

It all depends on YOUR rifle... Have you tried the 105gr BTHP or 108gr ELD-M ?

My Savage factory barrel was the same, it shot 100gr factory loaded Interloc's OK but nothing heavier than that would shoot decent.

[Dick284]

Recommended barrel twist rate for the 103 grain ELDX is 1 in 8, your Ruger has a 1 in 9 twist barrel…… that’s why the poor accuracy.

[elkhunter11]

The eldx is a long bullet for the weight, so it requires a tighter twist than many bullets of similar weight.

[MaxxiD]

Yeah, I figured it was just a gun to ammo issue.

Honestly, the power shok shoots lights out! Might try the btsp next.

I would stick with the factory ammo, but I just spent a bunch of money on reloading gear haha

[Peppysan]

I can first hand verify that the Ruger, (mine is an M77 HB 1:10twist) won't like the .243cal 103g ELD-X.
I ran out of the Hornady Amax 105's and picked up the 103's thinking how different can they be. DUH
Tried 5 different loads and two different powders and they were not grouping better that 2moa. The Amax were like 0.6moa.

I have a Ruger Precision Rifle in .243 and a 1:7.7" twist, I hope they work in that barrel.

A question I do have is; do you include the length of the plastic tip when you measure the bullet length, to use in a Twist Rate Calculator?

[Smokinyotes]

How big is a “lights out” group.

[6.5 shooter]

It is all about bearing surface. Long pointy bullets with long boat tails have less, then round nose bullets with flatter bases. (More pointy, more barrel twist, all things being equal) velocity also factors into the equation. BR guys generally prefer flat base bullets over boat tails, due to them being more accurate.

[Dick284]

Originally Posted by 6.5 shooter

It is all about bearing surface. Long pointy bullets with long boat tails have less, then round nose bullets with flatter bases. (More pointy, more barrel twist, all things being equal) velocity also factors into the equation. BR guys generally prefer flat base bullets over boat tails, due to them being more accurate.

Not driven by bearing surface but overall length of the projectile.

[Dick284]

Originally Posted by Dick284

Not driven by bearing surface but overall length of the projectile.

Further to this it is far easier and easily replicated to build simple designed bullet, the more steps in the process to build a bullet the higher the likelihood of having something take the QC into the ditch. That’s why the SBR guys run plain base bullets, plus they don’t need all the variable inducing features for the distances they shoot.

[catnthehat]

MaxxiD ,this is an older thread for sure, and I'm sure you have things figured out by now but if you didn't , it's in the two vastly different shaped bullets as has been noted
The easy solution is to shoot a 100 grain bullet with a shorter overall length .
A Hornady Interlock or Seirra Game King should work a lot better.
Cat

[6.5 shooter]

Low drag long range rifle bullets tend to have a long skinny nose, which places the center of mass somewhere towards the back of the bullet, meanwhile the center of pressure is somewhere up by the nose. The distance between these two points creates a "moment arm" that tried to overturn the bullet, because the aerodynamic pressure is acting on the center of pressure.

So, "length" of bullet IS a more direct metric than "weight" for determining needed rifling twist, but an even MORE direct metric yet is distance between center of mass and center of pressure.

A bullet with a really long bearing surface will TEND to have less overturning torque because that long bearing surface will generally result in a shorter ogive (assuming both bullets are same diameter and very similar weight). Thus, that bullet with the long bearing surface will tend to require less twist for stabilization.

[MaxxiD]

Originally Posted by catnthehat

MaxxiD ,this is an older thread for sure, and I'm sure you have things figured out by now but if you didn't , it's in the two vastly different shaped bullets as has been noted
The easy solution is to shoot a 100 grain bullet with a shorter overall length .
A Hornady Interlock or Seirra Game King should work a lot better.
Cat

This certainly is an old thread haha. I didn't even realize it had been resurrected.

I did NOT change the bullet, in fact I changed the rifle. Now sitting the eld-m out of a Tikka 243 with a 1:7 twist.

Never looking back!

[MaxxiD]

Originally Posted by Smokinyotes

How big is a “lights out” group.

Well.........

[Rhino81]

I’m sending 212gr eld-x from my hells canyon 300prc and the gun loves them. I dont miss with it. The gun groups fantastic out to 500. Im shooting off my bench and I’m confident they will group fairly tight out beyond 500

[Pioneer2]

Is it a 1-8" twist ?