88's in my 8 twist Tikka

[Steve Ladino]

At the range again today with my Tikka 8 tw. and the 88 grain ELDM bullets. I usually shoot the 77 grain TMK's but was wondering if it would stabilize the 88's. Starting low with 22.6 grains of Varget they key holed @ 2400 fps. @ 100 yds. yesterday. Today I shot some with 24 grains of Varget @ 2600 FPS,
these did not key hole, but showed a typical vertical spread. Bottom line is I think with more or perhaps another faster powder they will be a winner in the Tikka. When we get another good day I will try them at 300 yds. to see how consistent they perform.

 

[DukeDuke]

I tried them a few times in my 1-8" ar and they were not good, no keyholes but not consistent at all
shoot great in 1-7" twist at 2850 fps

 

[Nightraider]

Need a 7.5

 

[Longtrain]

I shoot 300 yard FClass with my 223AI with a 30” 1:8 barrel, it hammers with 80.5 Berger’s. It will be awhile before that barrel is taken off (unless I get an itch to do it before hand), but the 85.5 Berger’s are intriguing. Based on guesstimates it may shoot 1/2 MOA tighter at 600 yards then the 80.5’s. So, a lot of 9’s may hold the 10 ring. Looks like that barrel will need to be a 1:7 twist, an 8’s not going to do it.

 

[Hohn]

I ordered a 7 twist expecting that getting full BC from the 88s would require a 7 twist.

 

[Steve Ladino]

I ordered a 7 twist expecting that getting full BC from the 88s would require a 7 twist.

I shoot them in my 22-250 AI 7 twist and you are right according to my results but still going to work with the .223 for now.

 

[Ned Ludd]

The fact that the 88s were keyholing with a lower charge weight/velocity is indicative of a very low gyroscopic stability coefficient (Sg), probably less than about 1.1 or so. It takes a significant increase in velocity to have a noticeable impact on stability, so increasing velocity will improve the Sg only marginally. If they no longer keyhole at the higher velocity you may be able to get away with using them, but to what point? You're giving up a significant amount of the intrinsic BC of that bullet, one of its best attributes. Why not try the 80 ELDM instead, which is listed by Hornady as requiring only a minimum 8-twist barrel?

 

[Hohn]

Thank you Ned for highlighting how poor a lever speed is for stability. A lot of guys seem to think they can turn an unstable bullet in to a stable one just by stepping on the gas pedal. That's rarely the case.

 

[Longtrain]

[QUOTE="...A lot of guys seem to think they can turn an unstable bullet in to a stable one just by stepping on the gas pedal. That's rarely the case.[/QUOTE]

It’s really quite simple, Berger and other manufacturers did all the hard work and figured out what twist you’ll need for maximum stability for a given bullet. When you decide to shoot a bullet in a lesser twist barrel and it doesn’t perform, in spite of driving it harder, all you’re doing is throwing money at the target. With all we spend on our sport, you’d think we’d want the best possible results. If your 1:8 will shoot 80 grainers, learn to shoot them. When that barrel is toast decide from there what your needs are and go from there, you won’t be disappointed trying to put a square peg in a round hole.

 

[Steve Ladino]

Nothing ventured , nothing gained is a philosophy that makes for an exciting life but in this case the 88's did not perform accurately at long range in the 8 twist even with almost 400 more FPS. I agree that the 80 some range of bullet weights do really well in the 8 twist and for now I'll continue with the 77 TMK's. Thanks All for your input .

 

[xswanted]

How about the 85.5 Bergers? Maybe give those a shot if you want heavier than 80.

My T3x Varmint loves 80 grain Sierra’s.

 

[Longtrain]

Berger 85.5’s @ 2950 FPS in a 1:8 is only marginally stable according to Berger’s calculator. You cannot push them fast enough in a 1:8 being stable without blowing something up or never being able to open the bolt. They really need a 1:7 to stretch their legs.

 

[Rdlningcltchdmpr]

At the range again today with my Tikka 8 tw. and the 88 grain ELDM bullets. I usually shoot the 77 grain TMK's but was wondering if it would stabilize the 88's. Starting low with 22.6 grains of Varget they key holed @ 2400 fps. @ 100 yds. yesterday. Today I shot some with 24 grains of Varget @ 2600 FPS,
these did not key hole, but showed a typical vertical spread. Bottom line is I think with more or perhaps another faster powder they will be a winner in the Tikka. When we get another good day I will try them at 300 yds. to see how consistent they perform.

Don't even bother. Additional speed won't help. Not even at 22-250 speed.

 

[grovey]

At the range again today with my Tikka 8 tw. and the 88 grain ELDM bullets. I usually shoot the 77 grain TMK's but was wondering if it would stabilize the 88's. Starting low with 22.6 grains of Varget they key holed @ 2400 fps. @ 100 yds. yesterday. Today I shot some with 24 grains of Varget @ 2600 FPS,
these did not key hole, but showed a typical vertical spread. Bottom line is I think with more or perhaps another faster powder they will be a winner in the Tikka. When we get another good day I will try them at 300 yds. to see how consistent they perform.

Now you know those slippery bullets are cheating. But hey, use those Hornady's and I may have a chance next time around. I've heard keyholing is even better for score shooting than a 30BR

 

[Steve Ladino]

Now you know those slippery bullets are cheating. But hey, use those Hornady's and I may have a chance next time around. I've heard keyholing is even better for score shooting than a 30BR

Yes.....wobble them in.....keeping the slippy ones for the 7 twist AI.

 

[XTR]

JBM

Berger

 

[xswanted]

How about the 85.5 Bergers? Maybe give those a shot if you want heavier than 80.

My T3x Varmint loves 80 grain Sierra’s.

Quoting my own post but I tried the 85.5s in my 223AI 8 twist.

They didn’t keyhole but very inconsistent through a couple different powder charges and powders.

Could be this rifle is a slow 8 twist, but I think even the 85.5 might need more than an 8 on average.