Hornady 225gr ELDM's

[steve123]

Thanks for the info Frank! I'll try the 90gr SMK next in my 223AI. It's Benchmark 6r.

Yeah, over at Saubier that 9 twist was the suggested twist at the time, like 5 years ago, for those 55's. Wish I'd ordered a slower twist. And well, gone with 20BR too.

Going with your 5r's if doing a shouldered barrel from now on. Would be cool if you'd start doing Savage prefits in 5r at some point!

Haven't had any problems with 6mmBR, 105 hybrid in a 8 twist, surprising huh?!

 

[FrankG]

Thanks for the info Frank! I'll try the 90gr SMK next in my 223AI. It's Benchmark 6r.

Yeah, over at Saubier that 9 twist was the suggested twist at the time, like 5 years ago, for those 55's. Wish I'd ordered a slower twist. And well, gone with 20BR too.

Going with your 5r's if doing a shouldered barrel from now on. Would be cool if you'd start doing Savage prefits in 5r at some point!

Haven't had any problems with 6mmBR, 105 hybrid in a 8 twist, surprising huh?!

Not on our website yet but we are offering prefit Savage 110 barrels.

Standard Savage small shank target contour and will finish at 26” or less.

6mm, 5R and I want to say 1-7.5 twist. I’d have to double check.
6.5mm 5R and 1-8 twist.
30cal. 5R and 1-10 twist.
SS

Later, Frank

 

[memilanuk]

Dang it, @FrankG

*LARGE* shank

**LARGE**

 

[Ned Ludd]

Thanks for the info Frank! I'll try the 90gr SMK next in my 223AI. It's Benchmark 6r.

Yeah, over at Saubier that 9 twist was the suggested twist at the time, like 5 years ago, for those 55's. Wish I'd ordered a slower twist. And well, gone with 20BR too.

Going with your 5r's if doing a shouldered barrel from now on. Would be cool if you'd start doing Savage prefits in 5r at some point!

Haven't had any problems with 6mmBR, 105 hybrid in a 8 twist, surprising huh?!

Steve - I've blown up both the Berger 90 VLDs and the Hornady 88 ELDMs in a 6.8-twist .218"/.224" 5R barrel at velocities comparable to what you mentioned, which are readily achievable in a standard .223 Rem cartridge. If you're blowing up .224" heavies under those conditions in a .223 AI, I would make the argument that you're not realistically able to take advantage of the extra horsepower available in that cartridge.

FWIW - some people have had success using a 7.0-twist rate 5R barrel, except with 0.219"/0.224" bore/groove dimensions, rather than 0.218"/0.224". Presumably, that configuration cuts about half a thousandth less deeply into the jacket and can make a big difference. I have yet to experience any jacket failures with the 90 gr SMK at comparable velocities from the same 6.8-twist rifle, suggesting they have a thicker and/or tougher jacket. Another option might be something like the 85.5 Hybrid, 80.5 Fullbore, 80 SMK, or 80 ELDM bullets. Although you'd be giving up some BC with those choices, they have shorter bearing surfaces and appear to stand up better to the high RPM and stresses that cause the 90 VLD and 88 ELDM jackets to fail.

 

[FrankG]

Steve - I've blown up both the Berger 90 VLDs and the Hornady 88 ELDMs in a 6.8-twist .218"/.224" 5R barrel at velocities comparable to what you mentioned, which are readily achievable in a standard .223 Rem cartridge. If you're blowing up .224" heavies under those conditions in a .223 AI, I would make the argument that you're not realistically able to take advantage of the extra horsepower available in that cartridge.

FWIW - some people have had success using a 7.0-twist rate 5R barrel, except with 0.219"/0.224" bore/groove dimensions, rather than 0.218"/0.224". Presumably, that configuration cuts about half a thousandth less deeply into the jacket and can make a big difference. I have yet to experience any jacket failures with the 90 gr SMK at comparable velocities from the same 6.8-twist rifle, suggesting they have a thicker and/or tougher jacket. Another option might be something like the 85.5 Hybrid, 80.5 Fullbore, 80 SMK, or 80 ELDM bullets. Although you'd be giving up some BC with those choices, they have shorter bearing surfaces and appear to stand up better to the high RPM and stresses that cause the 90 VLD and 88 ELDM jackets to fail.

In years past I use to shoot tight bore type barrels in 224 and 6mm and even 30.

I don’t anymore and haven’t for a while. If a guy insists on using a tight bore and tells me he wants a 4 groove I really try to push the 5R then and that’s why. The rifling is going to cut deeper into the bullet jacket. Your just asking for problems.

With good quality match type bullets....I really don’t see the need for a tight bore barrel.

 

[No i deer]

Would the 4 groove in my twist cause the 180gr ELDM's too blow in my 7mm saum then..??

 

[FrankG]

Would the 4 groove in my twist cause the 180gr ELDM's too blow in my 7mm saum then..??

Hard to say....I’ve shot plenty of 4 groove barrels in 6mm, 7mm, 6.5mm, 30cal, .224cal. Etc.....with no problems.

I have seen 4 groove barrels (won’t name maker) where the customer sent the rifle to me because it was blowing up Berger 180gr VLD’s. Barrel was in good shape and couldn’t find anything wrong with it. Caliber was 7STW (which stands for severe throat wear. LOL!) and the customer was running the bullets at like 3100fps. Yep bullets blew up when I shot them. Back when that happened (like around 2000) one of the guys at Berger at the time told me the bullets where only designed for around 2700fps. His other comments where pretty interesting. I shot 150 Nosler Ballistics and no bullets blew up.

So back to your question....at 2960fps in a 9 twist barrel and you have almost 1600 rounds on it. Your bullets are spinning at almost 237,000rpm.

I’ll say off hand.....I’ll say no the 4 groove shouldn’t be causing the problems and the bullets to blow up.

I will have to question the round count and when did you start seeing bullets blow up? Did the blow up from early on in the barrels life or after X amount of rounds where on the barrel? If after X amount of rounds on the barrel and lets just pick a number for now and say 1200 rounds. If that’s the case then I’m going to say that’s a indicator that the barrel is on it’s last legs. Also depending on how your cleaning it you might not be getting it clean enough. You could have a slight restriction in the throat area from carbon build up and this could be a cause or adding to the problem. Any damage in the bore from cleaning? Roughness on the edge of a land that your not seeing. Any damage to the driving side of the land will beat the bullet up more. Any damage or burr at the crown of the barrel?

Is it the same lot of bullets? If it’s the same lot try a different lot and see if it happens.

Interesting enough I was on the phone today with a ammo/bullet maker and in a round about way we got on this subject and we’ve talked about it in the past. If I remember to a past conversation with them we’ve made them spec. 4 groove barrels for 6.5mm and they have literally abused the barrels and could not get bullets to blow up. Even ones where customers sent them bullets back that where suppose to be blowing up. They couldn’t do it. Now some of the barrels have very high round count....and pushing the bullets hard they can get bullets to fail. So this brings me back to round count/barrel life being the culprit.

 

[No i deer]

Hi Frank.
Thanks again for your knowledge. All 15 boxes are the same lot number...
I'd say I started using the 180gr ELDM's at nearing 1500 round count and no missing shots til then using hybrids and scenars...!!

I did 3x4 shot test groups at 100yds.
Next shoot was at 1000yds and it became a 2 x 20 detail as fog caused a delay. All these made the target nicely.
22 shots plus 5 blow offs and a 3 shot HME card 30 shots altogether.
Next shoot 300yds. 3 for HME 5 blow offs 2 + 15 and 2 of these didn't make the target.. 5th and say 10th shot...
600yds next 2 + 15 and all shots made it to the target taking shot count to 1570..
It's been cleaned and unfired.
Next shoot is on the 26th and I've got the same ammo loaded too see how they go as it shot sub 1/4 minute elevations bar 1 shot at 600yds..
If I get any that doesn't make the target this time I will try the hybrids on the next match and if it blows any of them I will retire the barrel.
Thanks Neil

 

[No i deer]

Still nobody coming forward saying they've had the 30 cal 225gr ELDM's blowing up so this seems too be a good option..

 

[MikeMcCasland]

Still nobody coming forward saying they've had the 30 cal 225gr ELDM's blowing up so this seems too be a good option..

Eh, I'd still be very cautious; especially running them in a magnum 30 cal.

I've blown up ELDMs in multiple non-magnum calibers, where they weren't anywhere close to 300k RPM, have seen other competitors blow them up on the line, and talked with too many competitive shooters that I know/respect that have had the exact same experiences. You combine that with the reports you read on various forums, and it kinda starts to show a trend.

I understand what Frank is saying though; not all blow-ups are the same, and often times there are several factors. That said, I've seen and experienced enough of the ELDMs to ever want to shoot them in matches. Across 5R bartleins, 4 groove Kreigers, all borescoped every 100rd cleaning interval...it wasn't the barrels, or the twist/speed that did it.

Accurate - Yes
Inexpensive - Yes
Trusthworthy for record strings of fire - No.

Edit: Frank - Per your last post: 4G 8T 30" Krieger with ~2,000 rounds on it; BoreTech/JBed it and borescoped prior to blowing up 147 ELDMs (2800fps) on the 19th round of my 1st string. Throat looked amazingly good; could have passed for a barrel with 300 (no joke). I did all that prep work because I'd watched 147s blow up the previous match in a factory savage and was wary of it. Happened again after that match. 140 Hybrids stayed together no problem up to and after that point.