90 SMK vs 88 Hornady ELD loading

[Albany Mountain]

I'm going to try 88 Hornady ELD in my 6.5 twist gaintwist barrel. I have been shooting 90 sierra matchkings to now. does the 88 ELD have more bearing surface than the matchkings?? Would I expect similar pressures that I am getting with the sierras??

Thanks

 

[watercam]

A quick look at online images and comparing measurements there does not seem to be much difference between the two bearing surfaces. I, too, shoot the Sierra 90s and would be interested in your results. BCs are nearly identical for all intents and purposes.

 

[Ned Ludd]

I've used both. Here are some [average] BTO measurements I took using a comparator tool with the Hornady insert, which has a slightly smaller hole than a Sinclair insert, and therefore seats a little further out on the bullet ogive:

90 SMK - 0.6625"
88 ELDM - 0.6830"

So the 88 ELDM average BTO measurement was ~ .020" longer than the 90 SMK.

Here are the [average] G7 BCs estimated for both bullets using LabRadar velocity drop data:

90 SMK - 0.281
88 ELDM - 0.306

The main caveat with the 88s is simply that I've lost several jackets (i.e. jacket failures) in the specific rifle I was using, which has a 0.218"/0.224" bore/groove configuration, 6.8-twist, 30", 5R SS barrel, chambered with 0.220" freebore. For that reason, I cannot risk using them in matches, even though I would very much like to. In fairness, this is using FG-TR match loads, which are fairly stout (~2850 fps from a 30" barrel), although not stupidly so. The 90 SMKs have a much tougher jacket and I have not experienced any failures with them in that barrel. This barrel has also caused jacket failures with Berger 90 VLDs. In general, if someone really wants to use the 88 ELDMs, I would strongly suggest a much shorter barrel length than 30", going to a 0.219"/0.224" bore configuration, which has been suggested to be much easier on bullet jackets (i.e. not as tight), and/or not using twist rates faster than 7.0. Barrel length, tightness of the bore, and fast twist rates are all potential contributing factors to jacket failure. The SMK 90s are GTG in this regard. I was unable to cause any jacket failures using them in this rifle, even when I pushed them pretty hard.

Your gain-twist barrel may also turn the trick with regard to the 88 jackets, as they are reputed to be a little easier on jackets. It will likely be an issue of just having to test some and find out.

 

[clowdis]

The main caveat with the 88s is simply that I've lost several jackets (i.e. jacket failures) in the specific rifle I was using, which has a 0.218"/0.224" bore/groove configuration, 6.8-twist, 30", 5R SS barrel, chambered with 0.220" freebore. For that reason, I cannot risk using them in matches, even though I would very much like to.

I also lost a couple of jackets at a match at Camp Lejeune a week ago on my 88 ELDM's. I'm going to try them again at a match this weekend in Butner after moly coating them. Going to use the same load of CFE223. Hopefully the moly will add enough lubrication so the jackets will resist tearing. I'm pushing them at 2880 fps through a 6.5 twist bore. I don't remember what the bore diameter was. A very good bullet that shoots and "carries" well in the wind and I'd really like to get this one to work.

 

[clowdis]

Well, moly coated bullets don't do any better. I was still blowing them up. Guess this bullet just isn't going to make the cut.

 

[Jdne5b]

6.5tw is unnecessarily fast for pretty much any of the .224 bullets out there. Even the Sierra 95 shoots in a 7 twist at 2750fps for me. I've tried a 6twist and didn't see any benefits on target. Although it is a .219 and hasn't blown any bullets up yet while testing 90vld, 88eld, 95smk. I'm going to get it back out to use up some of my leftover components, we'll see if adding more rounds will blow any up.

 

[Rtheurer]

I have been running the 88 ELD in my 223 Palma RIfle with no issues so far. Its a 30" 1:7 Twist 3 groove PacNor (before the building burned down) Next bullet i will test is the 90gr SMK as I have some on order.
Sure is fun to shoot that lil 223 out of a sling. Very pleasant to shoot.

 

[clowdis]

Russ,
How hard are you pushing them?

 

[clowdis]

Well I guess I did the smart thing and called Hornady tech service and talked to them about it. What they said was that the ELD-M is good for about 290,000 rpm and I'm pushing them at 319,000. So I guess I shouldn't expect them to stay together. So, running through the numbers backwards, it looks like I need a 7.5 twist barrel if I want to run the ELD-M's at 2900 fps. That would put them safely under the 290,000 rpm max that Hornady recommends. So I guess I need to go ahead and get another barrel on order!

 

[calgarycanada]

Well I guess I did the smart thing and called Hornady tech service and talked to them about it. What they said was that the ELD-M is good for about 290,000 rpm and I'm pushing them at 319,000. So I guess I shouldn't expect them to stay together. So, running through the numbers backwards, it looks like I need a 7.5 twist barrel if I want to run the ELD-M's at 2900 fps. That would put them safely under the 290,000 rpm max that Hornady recommends. So I guess I need to go ahead and get another barrel on order!

Interesting, that would limit 223 with1-7” twist at 2850fps, which is pretty much spot on for 223 velocity node.

 

[rcgill]

Blair,
My loads......
90 VLD = 301,000 rpm
85.5 Hybrid = 312,000 rpm
7 twist .218 x .224
Bob

 

[clowdis]

Thanks Bob! I haven't tried the VLD's but I have shot the 85.5 with no issues. I just think the ELD-M would be a better bullet IF you could get all of them to the target. In the meantime I have the .308 and it works fine so I'll use it until I think I've got all I can get out of the .223. Funny thing, we're probably talking about and trying to achieve numbers so small they're probably meaningless. But some people (and you're one) seem to shoot the .223 exceedingly well and that's where I think the success lies. I don't think it has to be ballistically better than the Palma round, just equal for it to be accepted universally in Palma competition because it's easier to shoot.

 

[Ned Ludd]

Well I guess I did the smart thing and called Hornady tech service and talked to them about it. What they said was that the ELD-M is good for about 290,000 rpm and I'm pushing them at 319,000. So I guess I shouldn't expect them to stay together. So, running through the numbers backwards, it looks like I need a 7.5 twist barrel if I want to run the ELD-M's at 2900 fps. That would put them safely under the 290,000 rpm max that Hornady recommends. So I guess I need to go ahead and get another barrel on order!

The RPM values are only one facet of why bullet jackets fail, and not always the best indicator other than using them as a "Yes/No" kind of readout. Berger will tell you that if you spin their bullets over 300K RPM, all bets on the jackets surviving are also off. From my experience, running the ELDMs at 2900+ fps is the problem, and you will not be able to solve that simply by using a 7.5-twist barrel. A better approach would be to slow them down to the 2850-ish fps range (or less). If you only decrease the twist rate by half an inch, the 2900 fps velocity is not enough to overcome the decreased twist rate and a much lower and unfavorable gyroscopic stability coefficient would be the result. In other words, with a 7.5-twist barrel you'd end up giving up a fair bit of the BC which is the primary reason for using such long/heavy bullets in the first place, and might even notice a detectable decrease in precision.

It would be far better to simply use a 0.219" bore barrel in 7-twist as Jeremy suggested above. It is not 100% clear to me whether you reliably hit the 2900+ fps mark without fear of jacket failure using the 88s with such a barrel, but the odds of it working would be much better than a 6.5-twist/0.218" bore barrel.

Interesting, that would limit 223 with1-7” twist at 2850fps, which is pretty much spot on for 223 velocity node.

This is exactly why IMO switching to something like the .223AI isn't a viable alternative for getting more velocity out of heavy bullets than the parent .223 Rem cartridge itself can generate. There are several limiting factors that all seem to become substantial in that same velocity/pressure region. Obviously, exceeding the suggested upper limit for RPM/friction and causing jacket failures is one. The other is that when loading the 88-90+ gr bullets over H4895, which is an outstanding powder for that purpose, ~2850 fps is also the point where pressure, primer pocket expansion, and poor brass life becomes a noticeable issue. It seems as though Mother Nature has provided a well-defined upper limit in .223 Rem performance for us through the wonders of physics.

 

[clowdis]

The RPM values are only one facet of why bullet jackets fail, and not always the best indicator other than using them as a "Yes/No" kind of readout. Berger will tell you that if you spin their bullets over 300K RPM, all bets on the jackets surviving are also off. From my experience, running the ELDMs at 2900+ fps is the problem, and you will not be able to solve that simply by using a 7.5-twist barrel. A better approach would be to slow them down to the 2850-ish fps range (or less). If you only decrease the twist rate by half an inch, the 2900 fps velocity is not enough to overcome the decreased twist rate and a much lower and unfavorable gyroscopic stability coefficient would be the result. In other words, with a 7.5-twist barrel you'd end up giving up a fair bit of the BC which is the primary reason for using such long/heavy bullets in the first place, and might even notice a detectable decrease in precision.

Using a 7 twist barrel and pushing the ELD at 2850 is almost exactly where the tech at Hornady said it should be, so I understand the accuracy node there. I also realize that changing those "standards" can upset the applecart and make you start all over again. But 2900fps seems to be the place where the .223 becomes competitive with the .308 and with the newer powders I've heard of shooters pushing the Bergers to near 3,000. "I've heard" being the key here because I don't know of anyone running near that velocity. I've been near there myself with CFE223 but accuracy was crappy to say the least. I think we will have to accept something in the area of 2850fps to 2925fps and learn to be happy with it. I think that is easily achievable.

 

[davidjoe]

I hesitate to throw this thought into the mix. On ranges using e-targets, and that is a lot of them now, you would really have to be blowing up a fair number of bullets in the same match, before it would become evident that was going on.

I have seen a lot of shots not picked up over the months, and from guns like .308’a that don’t blow up bullets and send down big bullets that are very hard for the system to miss, yet they can indeed fail to register them. If no one received a crossfire the practice is to shoot again, consistent with the newish rule.

I bring this up because at etarget matches, if you fire prematurely and miss the whole target, (and the other targets), blow up a bullet, call the wind so badly you miss, have a muscle spasm. lob a poorly loaded squib round 1/2 way down the range, get unlucky and hit a bird, fire when repositioning from bad trigger discipline, or - and this happens too, set your trigger too light and shall we say send one autonomously, but aligned more or less … it is all very hard to know that the target didn’t simply fail to register your shot.

If you have been shooting well, you get to reshoot. You might suspect a mishap on your part but if it had happened to you and others when no one suspected a mishap, then it’s really asking a lot of a shooter to penalize himself without knowing for certain, based on the possibility that that the target didn’t fail. I have been a tad surprised I pulled the trigger hard enough to fire and instead of an 8 braced for, gotten the X.

An exception to this involved a rifle where shooters could watch frequent visible blowups of big 180 grain bullets, that were regularly occurring, but only because they started looking for them.

I received a delivery of these today and look forward to trying them. I’m kind of wondering now reading through carefully, what’s the likelihood of blowups been with them, once in a warm season, … once a match, if the barrel is hot? Of course the really grizzly question, ever back to back?

 

[Ned Ludd]

I've never yet caused a bullet jacket of any kind to fail with a 90 VLD when pushing them at 2840-2850 fps with H4895 in a 30" 0.218"/0.224" 7-twist barrel. However, I think it's very close to the edge. I say that because my issues with jacket failures using the 90 VLDs and 88 ELDMs came using a 30" 0.218"/0.224" 6.8-twist barrel. My guess is that running these at 2900+ might be the straw that broke the camel's back with respect to jacket failure, even if using a 7-twist barrel (i.e. 0.218" bore). It would certainly be so with respect to killing the primer pockets in a single firing. All my future barrels will be 0.219" bore for that reason. It is possible that achieving 2900+ fps velocities might be possible without the brass life issue if using a double base powder, rather than something like H4895. However, those powders can sometimes present an entirely new issue (velocity variance) during the long strings of fire we typically shoot in F-Class matches, so I've always stuck with the single base powders like H4895 and Varget. As you noted, the performance with the .224" heavies at that inflection point is tantalizingly close to that of a .308 Win with 200s. It may be that it can be successfully reached with just the right combination of powder choice, barrel length, freebore length, and twist rate, without compromising jacket integrity or brass life. However, my motivation to test all those different variables in an effort to come up with just the right combination isn't what it used to be.

 

[Ned Ludd]

...I received a delivery of these today and look forward to trying them. I’m kind of wondering now reading through carefully, what’s the likelihood of blowups been with them, once in a warm season, … once a match, if the barrel is hot? Of course the really grizzly question, ever back to back?

In my hands with the 30" 0.218"/0.224" 6.8-twist barrel that caused jacket failures, the first time it ever happened was in a match on a very hot day where I was actually leading at the time. In the 3rd match of the day about 16 rounds in, a shot came up dead center horizontally, but was in the 7-ring straight low. The next shot failed to reach the target. The next three shots were fine, as were the final 20 shots in the 4th match of the day. After that event, I started running a couple patches wet with Kroil down the barrel after each string, followed by three dry patches, just to get a lot of the carbon fouling out before the next string. That approach seemed to work, because I never lost another 90 VLD when implementing it. Needless to say, when shooting in an F-Class match, even a single jacket failure is too many.

However, when I first started testing the 88 ELDMs, at a similar point in terms of the total number of rounds down the barrel during that particular shooting session (~50 rounds in), I started losing jackets, including several in a row. My guess is that you reach a point where the barrel fouling/carbon buildup and heat simply become too great. Because I was doing preliminary load development at 100 yd, some of the bullet remnants actually hit the target, although not close to where they should have impacted. On a couple shot holes, it was clear from the shape of the hole that a piece of the jacket was hanging off the bullet as it passed through the target. From the testing I had done up to that point, I was very pleased with the 88s; they really grouped well. I think it can really be a winning bullet in F-TR if the propensity for jacket failure can be mitigated. From other people's results, I believe the 0.219" bore is that most expedient way to do that, without markedly sacrificing performance by slowing the load down by 75-100 fps.

 

[Rtheurer]

S

Russ,
How hard are you pushing them?

Sorry for the Late reply Blair.
2850fps I am running the 88ELD at. Any harder and I loose Primer pockets in my brass in one firing.

 

[rcgill]

Prior to ICFRA changing the 223 bullet weight I shot the 80 ELD (best BC in that weight class) in the same set up as above without failure.
RPM was near 320k

 

[clowdis]

Prior to ICFRA changing the 223 bullet weight I shot the 80 ELD (best BC in that weight class) in the same set up as above without failure.
RPM was near 320k

Bob you've always had a "special magic" with that caliber that others have had problems duplicating. On the other hand it may just be how well you point the thing! Anyway, I ordered a couple of 7 1/2 twist barrels today from Brux but it'll be 5 months before I can test anything. It may just be $600 down the tube but what else do I have to do? In the meantime I think I'll just try some slower loads and see if I can keep things together.