223 Rem/ 90 berger/JLK max barrel length??

[rost495]

For those that have done this... whats the point of no return on the above? Standard 223 basically IE a match type chamber probably exactly the 223 Holliger Reamer.

I"ve talked with quite a few AR15 match shooters, and seems that 26-28 may be as long as you can utilize. But has anyone actually ran a 30-32 or so inch tube and gained more speed?

Thanks, Jeff

 

[2644ever]

According to QuickLoad, a change from 28" to 32" would add about 70 fps with a 90 grainer, if you use a powder in the N540 vivacity range. 2790+fps is not bad at all and you just have to add the length of a cigarette to your 28 incher.

 

[rost495]

2720 is what I got out of my 20 inch service rifles with N540 and 90 jlks.... 2790 gain isn't worth the effort and I'd take a stiffer tube if all I gained was 70 fps for 12 more inches or so of tube....

 

[Steve Blair]

I think that Laurie Holland has obtained much higher velocities and still shot excellent scores at long range. I do not remember his .223 load combinations but a quick forum search should turn up some of his posts.

 

[cmillard]

laurie was shooting varget with the 90s out of a 31" Truflite

 

[Taildrag15X]

With a Krieger 1-7" CM, 28" long I'm pushing them at over 2,800 using Varget.

 

[rost495]

I'll look for Lauries posts.... but getting X with a 31 isn't the answer I'm after... is 31 faster than 29 and would 33 be faster or slower....

Thanks for the idea of searching Lauries posts... maybe I can PM him.

 

[flatlander]

Jeff,
Jerry Tierny did a BUNCH of testing with Berger 90s; I believe he started with a 32" bbl. and shortened it down to 28" before seeing any significant loss of velocity. He used mainly RL15 & N550 to get the velocity he was after for Palma shooting with the 223, and posted a whole lot of data - perhaps the most comprehensive testing I've ever seen anyone do with 90s, let alone take the time to share it with forum members.

My first AR SR bbl. for the 90s was a PacNor 3-groove 1:6.5tw from John H. I could get 2715fps & good accuracy out of it with N540, but bump the charge .2gr, and groups really opened up. Tried N550; got 2812fps and even better accuracy. Then we got into a lot of JLK90s that Jimmy brought to Perry in '03, and everything went sour. I stopped shooting 90s & 6.5tw. bbls., and didn't mess with them again until last year, when I found that those 'bad' 90s would easily hold the X-ring at 600 on the MR-1 out of a 7.5tw. PacNor on my M70. Who knew that a 1:7.5tw would stabilize them?

Now I've got a 24" Krieger 1:7 on an AR, and am having good results with left-over SR ammo loaded with JLK 90s. Next will be an optical A4 SR with a 1:7 Krieger. Eventually, I'm going to try a 30" std. Palma bbl. w/1:7.4tw on an Eliseo tubegun, and see if it's a viable alternative to shooting the 308 in Palma matches.

 

[manitou210]

Friend has a 32" Tru Flite 1/7 mine is a 30" Tru Flite same load same bullet 90gr Begers the 30" is 18 fps faster, 28 kreiger 7" twist is 30fps slower.
We took the 90s VLD to 2940 fps no accuracy and lapua brass you might get 2 to 4 rounds fired and primer pockets are done, evedn at 2845 primer pockets get loose

 

[Laurie]

Here's the thread in the US Rifle Teams' Long Range Shooting Forum:

http://www.usrifleteams.com/lrforum/index.php?showtopic=11795

Jerry Tierney saw a c. 25 fps drop with 80s cutting his 1-7.7" Krieger down from 32 to 28".

I'll get a feel myself as my 31" True-Flite 1-7" is now shot out and the rifle is being rebarrelled in the next week or so. The replacement is identical to the original (True-Flite heavy Palma profile button rifled 1-7" twist 6-groove), but I've specified 28" final length this time round. Results won't be definitive as two barrels from the same maker with identical specs can still produce significantly different MVs, but it should give an idea.

Incidentally, my present set-up sees 2,850 fps with the 90gn Berger VLD and VarGet. Lapua case life is excellent with primer pockets still tight after six firings when I retire them from long-range competition. last year's Re15 load was hotter giving 2,907 fps and I never had to retire a case due to primer pocket expansion. But note, this only applies to the VLD. the Berger 90gn BTLR has a much thicker jacket and generates considerably higher pressures / lower velocities with both Re15 and VarGet loads needing reducing by 0.5-0.6gn, a lot in this cartridge.

Laurie,
York, England

 

[cmillard]

laurie, what was the round count on that barrel? did it just stop shooting?