TargetTalk

Looking at my dwindling supplies I am going to have buy some ammo soon.

Does anyone have any experience or notice a difference in the way wind effects the EPS bullet vs the more traditional round nose slug?

Thanks
'Dude

Over on the Delphi Forums Smallbore Accuracy website there has been a lot of comment that touched on this subject. Mike Barron

We did some experimenting with the EPS dimpled bullet versus regular SK+ at 100 meters. The EPS definetely performed better in the wind with regards to drift. We didn't get all scientific about it just edge breaks with full value consistant wind blowing pretty good. The EPS had arund .75" or so less drift compared to the SK+. For just pure accuracy the SK I was using shot about the same group size in ideal conditions as the EPS so the only plus was the wind bucking which is big at windy times but not worth another $5 a box or more IMO, I'll just hold off :)

The thing i like most about the EPS bullet are the pretty little holes that they make.
matt

Bowman26 wrote:We did some experimenting with the EPS dimpled bullet versus regular SK+ at 100 meters. The EPS definetely performed better in the wind with regards to drift. We didn't get all scientific about it just edge breaks with full value consistant wind blowing pretty good. The EPS had arund .75" or so less drift compared to the SK+. For just pure accuracy the SK I was using shot about the same group size in ideal conditions as the EPS so the only plus was the wind bucking which is big at windy times but not worth another $5 a box or more IMO, I'll just hold off :)

Funnily, I (and a few others) have found the exact opposite, when comparing Tenex to Lapua Midas+ - the Tenex took much more wind at 50m, the Lapua a LOT less so. By Eleys's own admission, the nose shape isn't critical to accuracy, and proved by disfiguring them with pliers prior to shooting.

The BASE of the head is more critical to airflow and stability

Anonymous wrote:Funnily, I (and a few others) have found the exact opposite, when comparing Tenex to Lapua Midas+ - the Tenex took much more wind at 50m, the Lapua a LOT less so.

Was that an average from across a range of velocities for each brand, or just 1 or 2 batches of each ? Obviously comparing a slow batch of Tenex against a fast batch of Midas is going to give different results to a slow batch of Midas vs a fast batch of Tenex. Just interested to know :)

Hemmers wrote:

Anonymous wrote:Funnily, I (and a few others) have found the exact opposite, when comparing Tenex to Lapua Midas+ - the Tenex took much more wind at 50m, the Lapua a LOT less so.

Was that an average from across a range of velocities for each brand, or just 1 or 2 batches of each ? Obviously comparing a slow batch of Tenex against a fast batch of Midas is going to give different results to a slow batch of Midas vs a fast batch of Tenex. Just interested to know :)

Tenex was 1065, Lapua was 1067 so very similar speeds.

I haven't heard whether anyone here has compared TESTED EPS to another TESTED lot of ammo. How do you know the two types you are comparing are even comparable without having done considerable testing ahead of time, purchased lots of each type that work exceptionally well in your gun (and they'd have to be equally as good as each other), tuned them, and fired them from your shoulder to see if there are any discrepancies?

You simply cannot take a box off the shelf of ANY brand, regardless of their rank in the world market, and test them side by side without a massive amount of preliminary analysis.

Are we to assume that these steps have been taken before the comparisons/tests that have been discussed in the previous posts? If they haven't, then the results you are posting are not empirical in the slightest. Not to be harsh. But....

BartP

You simply cannot take a box off the shelf of ANY brand, regardless of their rank in the world market, and test them side by side without a massive amount of preliminary analysis.

In my experience, the effects of wind on a 22 cal bullet at 50m will be noticable even if the ammo is only decent, not perfectly matched.

Ah yes, in a perfect world this would be done with at least two lots, one EPS, one traditional matched to the barrel and chronographed for velocity. Then a few days where the wind was just perfectly consistent. Best yet, time in a 50m wide wind tunnel to sort all of this out. ....I once worked with a fellow my supervisor would say often got stalled by "analysis paralysis" We as humans (and in my case an engineer) can make a problem so complex that no solution can possibly be obtained so we should just give up. To get a discussion started assumptions and approximations are just fine.

With my original post I was looking for some qualitative impressions. EPS has not been out long enough for a significant database to be developed. From the qualitiative impressions seems the results are mixed. One person says the EPS definitely performs better, another, the Lapua with the round nose. OK back to square one.

The basis for my question would be in having practice ammo and match ammo. Lets stay within the Eley brand for the discussion. Lets say I am shooting EPS Tenex for matches (36 cents a shot) but I need to watch my training $$ so want to shoot something a little more economical. OK so to stay with the EPS bullet I have to buy "Team" (22 cents a shot) for training. That still hurts my wallet big time. Looking down the line there is "Club" at 13.4 cents per shot or "Target" at 9.6 cents a shot. That is a little more palatable but for doping the wind would the two bullets behave similarly enough to get the full benefit of the training?

These are the kinds of questions I ask myself on slow afternoons. Perhaps it is just an academic discussion or perhaps it is a real issue. I guess time will tell.


Cheers,
'Dude

Since the wind drift characteristics for both bullet designs can be quantified by calculating a drag coefficient and/or BC for each, it “is” possible to conduct testing with the rigorous control necessary for making definitive conclusions. However, it’s not easy and thus far I’ve only obtained “sample specific” results which support the Round Nose being balistically superior to the Flat Point.

The post below is a copy & paste from the Smallbore Forum at Delphi
http://forums.delphiforums.com/n/mb/mes ... msg=103.39

“Mike,
This might be an appropriate place to report about some testing I did a couple of months ago in an attempt to determine which is balistically superior. The Eley Flat Point or the Eley Round Nose bullet.
My blog on BRC http://benchrest.com/entry.php?62-Chron ... l-(Part-1) details the time/effort I spent to very carefully calibrate each of my chronos and the end results of my testing were almost the same as yours at the beginning of this thread....the Round Nose showed a tiny advantage. However, that advantage was so small that it was statistically insignificant and for all intents and purposes these bullets behaved the same within the uncertainties I calculated for my equipment.
If I proceed with more testing, I’ll have to increase the distance between my chronos “and” the screen spacing for each of them to lower the uncertainties, but it appears that if their does end up being a difference....it’ll be fairly small and probably not as observable on target as some have suggested.
Landy”

Here’s another link with some related information for those who have an interest in this subject:
http://forums.delphiforums.com/Smallbor ... ?msg=270.1

Landy

Since the wind drift characteristics for both bullet designs can be quantified by calculating a drag coefficient and/or BC for each, it “is” possible to conduct testing with the rigorous control necessary for making definitive conclusions. However, it’s not easy and thus far I’ve only obtained “sample specific” results which support the Round Nose being balistically superior to the Flat Point.

This quote points to calculating a drag coefficient for the projectile. I had to read this twice but it seems aways curious is calculating based on chono data. For completely paper studies there are guidelines and thumbrules for the Cd of various shaped bodies that will get a analysis started but would not have the resolution to say with certainty which slug had the advantage. In the end one page of data can be worth 10 pages of academic calculations. Then things can get really iffy for bluff bodies traveling at transonic velocities. Add in the fact that these transonic bodies are spinning at 45,000 RPM (1000 ft/sec with 16" twist) and the fluid mechanics get really interesting in a hurry.

This does provide some answer, for just getting down range in a hurry the round nose bullet is insignificantly superior to the flat nose bullet. This makes sense. This may mean the EPS slug would in flight just a tiny bit longer and more susecptible to effects from the wind but round and flat surfaces can have very different responsed to what is literally a head wind coming in off axis. However if the deflecting force from the wind and effects of flow component perpendicular to the axis of rotation were less on the EPS bullet then it might not make any difference, or perhaps the opposite is the case and longer flight time and greater deflection forces make EPS more susceptible to wind wind deflection.

I get the feeling, that in various precision shooting circles, this topic will be debated for some time to come.

Too bad I did not have some EPS with me this weekend, it was windy enough to be a great test day. Just a little qualitative research. :)

Cheers,
'Dude

westerngriz wrote:The thing i like most about the EPS bullet are the pretty little holes that they make.
matt

Yeah Matt i like those nice holes too, pitty it has nearly doubled in price in the last 5 or so years!! Damn sure the quality would not have done the same.

EPS has been out for about 10 years now. I think if there was a significant advantage to it, we would have seen a boom in its use by now. Sure, it's good stuff, better than average, and they charge a hefty prce for that. I think if there is a difference in how the wind knocks it around, that factor is not as significant as the grouping of the ammo/rifle combo, not as significant as the shooter's hold for that shot, and not as significant as the shooter's ability to read wind.

Case and point, I've been using Lapua Master L (Lapua's 3rd grade of ammo) for the past 7 years. In that time I've won 9 state and 5 regional championships, completed both distinguished medals for smallbore, and stayed in the top 30 at Perry in both 3p and prone all but once or twice. A lot of people who didn't know me at those matched scoffed at my ammo and 30 year old rifle vs their 20whatever and Midas/EPS.

My advice on buying ammo is to get 4-6 boxes of 100 of different lots in your price range, test them at you current torgue setting for what shoots best, then fiddle with the torque to maximize its grouping, and that'll probably do you just fine. No need to complicate things too much past that.