243 Bullet (In)Stability

[RepeatPete]

I’m new to Rokslide and as such have read the .223 thread and listened to the Shoot2Hunt podcast ballistics episode. I would like to use a more modern technology bullet like the 95 gr TMK or 90 gr ELD-X after having deer run pretty far with good shot placement and traditional 100gr hunting bullets. I have a 1:10 twist Browning A-bolt in .243 and have used the stability calculators to discover that neither one of these bullets stabilize very well in 1:10. The numbers are 1.05 and 1.15, respectively with under 1 being not stable and over 1.5 being fully stable.
My two questions are:

1. Has anyone used either of these bullets in a 1:10 twist 243? How’d it go?

2. What does bullet instability practically look like? True keyholing I think I’d recognize, but do groups just get larger? This would be for PA whitetails, so all shots will be under 350 yds.

 

[redneckbmxer24]

Never shot either of those bullets in anything, but I did shoot some 95gr classic hunters in a couple 10 twist 243's and they shot great and give similar performance. They basiclally penetrate a couple inches and blow up liquifying the insides. Berger and Federal both have factory loadings with them that you could try and see if they shoot in your rifle.

As far as what instability looks like it can open your groups up or keyhole, just depends on how unstable it is.

 

[wind gypsy]

Hornady says the 90 ELDx needs a 10 twist. How did you calc stability of that? The plastic tips can cause some misleading #'s if included in the total length.

 

[RepeatPete]

Never shot either of those bullets in anything, but I did shoot some 95gr classic hunters in a couple 10 twist 243's and they shot great and give similar performance. They basiclally penetrate a couple inches and blow up liquifying the insides. Berger and Federal both have factory loadings with them that you could try and see if they shoot in your rifle.

As far as what instability looks like it can open your groups up or keyhole, just depends on how unstable it is.

Thanks for the input. Good to hear about the Bergers - I’d read multiple reviews about inconsistent expansion with the VLD’s, but I would imagine the classics might be better.

Hornady says the 90 ELDx needs a 10 twist. How did you calc stability of that? The plastic tips can cause some misleading #'s if included in the total length.

Thanks! I didn’t know that about the plastic tip, I just ran the whole bullet OAL. And completely missed that Hornady specified a 1:10. I’ll try picking up a box of the factory loads to see what happens before I buy the bullets to reload.

 

[Mike 338]

Bullets that show "marginal" deserve a chance. Just try 'em. I have a 10 twist 243 that shoots Berger 95 gr. Pro Hunter's just fine. I live at about 2800' elevation and hunt higher up so that would help the stability factor. You just gotta try 'em.

 

[wind gypsy]

Thanks for the input. Good to hear about the Bergers - I’d read multiple reviews about inconsistent expansion with the VLD’s, but I would imagine the classics might be better.

Thanks! I didn’t know that about the plastic tip, I just ran the whole bullet OAL. And completely missed that Hornady specified a 1:10. I’ll try picking up a box of the factory loads to see what happens before I buy the bullets to reload.

JBM stability calculator has a plastic tip length input if you want to give that a run.

JBM - Calculations - Stability

www.jbmballistics.com

 

[Bater]

90gr Eld-X keyholed in my 10T, 95 Berg Classic Hunters or 95NBT's are my go to's for a 10

 

[RepeatPete]

JBM was the calculator I was using, I just didn’t have a value for the tip length. Putting in a roughy 0.2” for the plastic tip length shot the stability number to 1.6. Well worth getting a box to try.

Thank for all the input,” - between the 95 gr Bergers and the ELD-X it looks like I’ve got some reloading work to do!