Which Cartridge for the 7mm 180gr ELD-M?

[Potss]

Stop. Please read the whole OP before responding.

The relatively new Hornady 7mm 180gr ELD-M has a G1 of .816 and a G7 of .411 when used in a 1:7.5 twist barrel. That is staggering. To get a higher BC (in a non-solid bullet) you need to step up about 100grs to a 285gr ELDM in .338. I want to build a new rifle for myself around this bullet. The question is which cartridge to use to launch it. The only criteria I have is that the cartridge should have relatively cheap and available factory ammo (for a number of reasons). This has narrowed it down to three choices:

1.) 7mm Rem Mag. Cheapest factory ammo by a good margin, mostly likely to find factory ammo in brick and mortar stores, most recoil, potential accuracy issues from belt, requires long action.

2.) 7mm WSM. Most expensive factory ammo (but still within reason), short neck, may require expensive 2.95 COAL mags for the 180gr loads if used in short action (or even require a long action to load to 3.05), more efficient than 7mmRem.

3.) 280AI. Cheaper factory ammo is 280 (non-AI) which may not be particularly accurate in the 280AI chamber, lowest recoil but gives up a few hundred FPS over other two, requires long action.

All would be using a 1:7.5 twist barrel to get the most out of the 180gr ELD-M. From messing around with online stabalization calculators it seems like the cheaper 140-160gr factory loads would be OK in that barrel, but I'm not 100% sure on that. Please chime in if that is not the case, because this build is predicated on being able to use factory ammo with the rifle in addition to the 180gr ELD-M loads. If they will work, then which of the three cartridges would you choose to run and why?

Or have I forgotten one?

 

[Delicatessen]

I shoot that out of a 284win with good results, bugholes bartlein 28” at 2880 fps. Factory ammo is pretty limited though. 280 AI, 7mm RM, or go nuts with a 28 Nosler would be good options too

 

[black max]

7saum built on a long action FTW!

 

[Conrad]

I’m running it in a SAUM seated long at 3.10”. Pushing 3050 FPS with R26. I still need to fine tune load and further verify the BC for my 1:8 barrel. When I shot it last at 1535 yards I had to bring the BC down a bit to match up.

7saum built on a long action FTW!

 

[Conrad]

For the ops question go 7 mag or 7 nosler if you want factory ammo. I have also loaded these in a friends 7 mag and they bugholed and cleanly took a bull elk for him.

 

[JBM_DC]

I had my Sako TRG Chambered in 7RM with a 1:7 Rock barrel at 27" and the thing shoots like a dream. During load workup I was able to get over 3k fps with the 180s on a fresh barrel. I never saw much in the way of ejector marks or extractor swipes on the brass. Only thing I noticed was a sudden change in the recoil to let me know I hit my max.

I chambered the 7RM for hunting so that I can walk into any local store and purchase ammo if I forget my ammo hundreds of miles away in my house like I am known to do. And when the 338 RUM barrel was screwed on I was a bit out of luck in the finding ammo department.

 

[harleytuner]

I'm building a 7mm Rem Mag right now around this bullet. I have part of the stock machined and am planning on chambering and threading the barrel this weekend.

 

[Mossyoak44]

I would go 7mm mag for the available ammo you can buy anywhere. I went through this about a year and half ago and ended up going with 7mm mag and don’t regret it. The biggest factor was ammo availability for me since I haven’t started reloading yet, which I plan on changing soon. I’m a big fan of 7mm cartridges and plan on building more.

 

[jLorenzo]

I think a 7 rem mag makes the most sense unless your just totally reloading. The Eld-x stuff from Hornady would be nice for factory stuff plus tons other.

 

[lennyo3034]

I'm using a 7mm Rem mag. 30" 1-8 barrel pushes the 180 ELDm at 3035.

That being said, I would hesitate to go with a 1-7.5 twist. Word is there is potential for these to overspin:

https://www.longrangehunting.com/threads/180-hornady-eld-m-bullets-blowing-up-in-air.202592/page-2

I don't "think" I've run into this issue, but there was one time shooting in the wind at 1100 where I couldn't see my impacts or misses.

 

[BoomerC]

I am waiting on a new barrel for my 7RM now. The one that is still on it is a 28” Brux. I was running the 180 eld m at 3041 suppressed. I also lost the barrel in 1018 rounds

 

[lennyo3034]

I am waiting on a new barrel for my 7RM now. The one that is still on it is a 28” Brux. I was running the 180 eld m at 3041 suppressed. I also lost the barrel in 1018 rounds

What was your load?

Mine is 71.9 of Retumbo.

 

[Potss]

Great info so far. The 7mm Rem Mag does seem like the best option but the link above does have me a little nervous at high velocities at a fast twist. Maybe 280AI is the solution if that problem persists, I may wait on the response from Hornady in the linked thread. It would suck to build a rifle for the higher BC only to have the bullet start blowing up.


....Maybe a gain-twist barrel would prevent this? Or maybe 5R rifling if they thing the grooves are causing it?

 

[BoomerC]

What was your load?

Mine is 71.9 of Retumbo.

68.5 if RL26

My barrel was a 1:9. New barrel is 1:8

 

[BoomerC]

Of*

also using Win brass. I was using PPU brass which was outstanding but had terrible case capacity. I was at 2940 and almost compressed. I was around 63gr with the PPU. Went to Winchester brass and at 68.5 with no pressure signs and a little more room left in the case.

 

[TorF]

In 7RM you should try Vithavuori N165/N170 powders with "diesel" loads for extended barrel life. A 180gr ELD-M@2800fps out of a 1-7.5" has "enough range" and the barrel should last 2000+ rounds. @2800fps the 180ELD-M is supersonic to app 2000yds.

In Scandinavia N160/N165 is known for long barrellife in 6.5x55 with 144gr bullets. At 2600-2700fps 4-5000 round barrellife is not uncommon.

 

[cottonant]

Skip the 7WSM...its a barrel burner from hell.

If recoil is an issue, especially if you will not be using a brake (which I hate), the 7Mag will preform better than the 280 with very manageable recoil.

 

[lennyo3034]

Did not know the 7 WSM was such a barrel burner. Does that mean the 7 SAUM will be too?

 

[matleez]

7-300 win mag would be able to push it at 3100 easily

 

[Potss]

Well Hornady isn't acknowledging the problems posted in that thread via email, so I guess I'm going to wait and see how it shakes out with the OP over there before pulling the trigger.

In terms of usable barrel life, I've heard with factory ammo the WSM and 7mm Rem Mag are around 1000 where as the .280AI is closer to 2000, what are folk's experience with this?

 

[BoomerC]

Well Hornady isn't acknowledging the problems posted in that thread via email, so I guess I'm going to wait and see how it shakes out with the OP over there before pulling the trigger.

In terms of usable barrel life, I've heard with factory ammo the WSM and 7mm Rem Mag are around 1000 where as the .280AI is closer to 2000, what are folk's experience with this?

Barrel life is what you make of it. You can easily get 1500 rounds out of a 7RM by not loading to the max and short strings of fire. I personally wouldn’t go with a 1:7.5. I would stick to the 1:8. There isn’t any reason to go with the 1:7.5 unless you were shooting the 195s or 197s out of it and even then depending on altitude, the 1:8 would stabilize them. I am at sea level in SC and stabilized the 180s fine. I couldn’t stabilize the 175 the eld x. They also have a longer bearing surface than the 180s.

Spin up a 1:8 at 28”, push the 180s 2950-3000 and roll with it.

 

[Potss]

I tend not to baby my barrels.

Looking at the .280AI, does anyone know what kind of accuracy could be expected with factory regular .280 ammo? I've heard both good and bad when fire forming, really unsure what to expect.

 

[Ledzep]

ELDM is a thin jacketed match bullet. That said, the jacket thickness of any ELDM should be enough to handle the RPM the poster in the link is pushing with his velocity and twist rate. After reading through the thread I'm pretty sure it's a loading/chamber/barrel issue the guy has. He spoke of having bad pressure issues with 195's before having bullets come apart with 180's... According to his numbers he's spinning them at 265,000 RPM which should be nowhere near fast enough to make them come apart. Not apples to apples, but I've run 95 grain Vmaxs (thinner jacket yet) in my 6.5 SAUM 1:8 twist @ 3900 fps and they don't spin apart (351,000 RPM).

There has been some evidence to show that even number of grooves (2, 4, 6, 8) and traditional squared off rifling profiles are more likely to cause stress concentrations in the jacket that lend to them letting loose. Proof barrels (what the guy in that link is using) are 4-groove with squared off rifling. How much more likely they are to cause it, I don't know...

Personally, I would go 7 SAUM in a long action with a 5R barrel and not look back.

 

[BoomerC]

You mentioned potential accuracy issues from belt on the 7RM.

Can you ellaborate on that’? Curious as to your reasoning behind it.

Mose ackleys are pretty accurate while fire forming unless it’s just a shitty barrel or Smith work.

 

[cottonant]

Did not know the 7 WSM was such a barrel burner. Does that mean the 7 SAUM will be too?

[/QUOTE] I tend not to baby my barrels. [/QUOTE]

Then stay away from the 7WSM for sure. I knew a guy that had a WSM burn out after 400 rounds shooting Benchrest.

I have no personal experience with the 7RSAUM so you will have to get that question answered from someone else but I've heard just the opposite, that they are not barrel burners. Kind of funny since the 7WSM and 7RSAUM cases are close to the same.

 

[jetmd]

Potss, you do whatever makes you happy. In the end that is what really matters.

After making that statement, I would look to the caliber you choose and get on anyone of several excellent suppliers:
Midway, Powder Valley, Wideners .....and order up 1K pieces of brand new brass then have the rifle built.

I have a 7wsm which I LOVE, 180 Bergers at 2950 and life is good. Brass availability not so great.
7 SAUM another great caliber. Brass availability not so great.

If I was building a brand new 7mm it would be a 7mm Rem Mag.

I would buy the best quality brass I could find, stack it deep and buy it often.

JMHO

 

[jetmd]

Barrel life, my 7wsm has over 1100 rds through it.

Still shoots like the day Moon built it. But I don't push it that hard. 180 Bergers at 2950.

Hopefully I didn't f**k myself by making that statement and the next 50 rounds end the life of my Schneider barrel ?

It could happen.

 

[tangodown]

7 SAUM would be my recommendation. Im running the SAUM on a short action. 28" Bartlett barrel 8 twist. I use Norma Brass, Nosler also makes brass for it. (Didn't go WSM because there is no real availability of 7 WSM brass and I don't like the fire forming and trimming game) I'm getting 2950 fps with a SD of 6. Shooting 0.25 MOA, mag feeding in a short action.

Here is my rifle and a target with 5, 5 round groups @ 300 yards.

 

[hereinaz]

I did 7mm mag, but if I had it to do again I would go 7 saum. Might consider the long action.

 

[hereinaz]

Forgot to add. When I reload, I headspace my 7 mag off of the shoulder by bumping .002 back. I don't headspace off the belt. It doesn't affect accuracy or feeding. I use Norma brass. Just started my second firing on a few pieces. I am sub .5 moa shooting 180 Berger VLD with 8.4 twist Proof Carbon Research barrel.

 

[7mmFanBoy]

no factory ammo 180eld , my 7mm rem 8.5 twist krieger 28" 180eld 2950-3050 .3 -.5 moa constant out 600 yards. Use annealed Remington brass with any powder

 

[D_TROS]

Ive got a 7wsm on a long action. OAL at 3.1 and shoots the 180's at 3000 with 26" Proof 4 groove and either 68 gr H1000 or 63 of 4831SC. This proof barrel really sings.

Im on my second barrel (1400 on my first barrel - shot it out at the SNipers hide cup in 2015 on an unlimited round mover stage and then an unlimited round KYL stage...bad idea lol). the 7wsm is no more of a barrel burner than any other 7, and I would argue less so than the 7rem as it holds less powder. It all depends on powder and how hot you are loading it. To a lesser extent the barrel/chamber. Shooting out a 7wsm in 400 rnds has nothing to do with the cartridge. chamber or barrel there or bad random fluke. The case deisgn and shoulder taper of the wsm would help barrel life if anything imo.

If I had to do it again, I would not go 7wsm as the brass is almost impossible to find (I had it for nearly 2 years before I got enough brass to shoot it in a match. I chose the wsm as its larger than the saum and I didn't want a belted mag. Also I read great things on its inherent accuracy. I won a match in WY and was 5th in a PRS match in OK with it.

If I had to do it again, I would prob go with 7-300 or just the wsm again. SAUM not a bad idea as brass is everywhere. It really doesn't matter, but I would recommend a long action to fully utilize the case capacity to let these 180's really sing. The bad part of a long action is you have to use a HUGE 10 rnd 300wm mag. Kinda lame but you get over it. ha. Also had to mill the rib out to fit the fat wsm in the mags.

Good luck! 7's are fun

Regards,
DT

 

[osu92]

Looking at the .280AI, does anyone know what kind of accuracy could be expected with factory regular .280 ammo? I've heard both good and bad when fire forming, really unsure what to expect.

My buddy and I build twin .280AI's a few years ago and to build up an inventory of brass, we shot Nosler Trophy Grade .280AI 140 Accubond blems bought through ShootersProShop. Accuracy with that ammo was always very good and we've actually shot quite a few animals with it as well as lots of practice rounds.

 

[LRShooter101]

The "Terrible 7mm Twosome"
Top - .284: Trued 700 Long Action, AICS, 30" Bartlein, Timmney. Use it for Long Range Prone Matches and 1,000 yard F-Open. It was used to win a 2,000 yard paper match, so yes it will go the distance. Running Berger 180 Hybrids at around 2,770 fps with around 53 grains of H4831SC in necked up Lapua 6.5-284 brass. GREAT ROUND! Good barrel life if you don't run your loads extremly hot. Great Lapua Brass, very easy to prep. Recoil is very manageable in a 19-20 pound rifle without a brake.

Bottom - 7 SAUM Trued 700 Short Action, AICS, 26" Bartlein, Badger FTE, Timmney. Use it for Longer Range PRS Style Matches. Running Berger 180 Hybrids at around 2,750 fps with around 64 grains of H1000 in Norma brass. GREAT ROUND! Good barrel life if you don't run your loads extremly hot. Recoil is very manageable in a 14-15 pound rifle with a brake.

I went with the .284 in a Long Action for situations where I do not need to run a mag, the size & weight of the rifle was not an issue, and I could NOT use a Brake due to match rules. I went with the 7 SAUM in Short Action so that I could run a mag, and so that is was a smaller & lighter rifle.

For me, it would come down to:
- How important is speed (knowing it will also cost you barrel life)?
- Do you need a higher capacity detachable mag?
- How important is factory ammo?
- Are you willing to reload, and how much time & money are you willing to put into it?

Fire away if you have any specific questions.

 

[Potss]

Thanks for all the advice so far, D_TROS that is an awesome setup you have there.

osu92 did you try 280 factory loads in your 280ai? It just seems the 280 are about 1/2 the price of the 280AI factory loads.

LRShooter101 that is a good set of questions and I'll answer them. I'm interested in any feedback you can give as you have two rifles close to the setups I'm considering:

- How important is speed (knowing it will also cost you barrel life)? A: I'd like to run them fast enough to justify running a 7mm over a 6.5mm CM. Basically the 147gr ELDM running at around 2700fps is very compelling from the 6.5CM which is going to have everything cheaper and more available to start with. I think around 2800fps is the break point.

- Do you need a higher capacity detachable mag? A: While it would be nice, I don't need it.

- How important is factory ammo? & Are you willing to reload, and how much time & money are you willing to put into it? A: Combined these because the answer is the same for both. My life right now and for at least the next 4-6 years is crammed enough that I basically have one small pool of "spare time" to pull from. So that time is either reloading or shooting, and obviously I want to be doing more shooting and less reloading in the small amount of time I have for it. So yes the ability to get quality factory ammo that isn't $2-3 per round is a pretty big deal, again especially in comparison to 6.5CM.

Let me know what you think.

 

[Conrad]

What is your primary objective?

 

[black max]

I dicked around with a 300wm for a while, then realized it was the 21st centry, hint hint...

 

[Old Dude]

I'm shooting 300 WM right now. The plan is to change to a 7/300 when the barrel goes. I'll have all that brass to fall back on. I'm only shooting Hornady brass to keep things the same. Brass was cheap. 76.5 grains H1000 208 grain Hornadys. I'm watching and learning from all these threads.

 

[Conrad]

6.5 creed will get 2900 FPS with R26 and 147s with a 25-26” barrel, FWIW.

 

[jakelly]

You want my opinion?
You are syncretizing several approaches and wasting your time.
With the criteria you’ve laid out, and the reasons behind it, you are absolutely not going to beat a Creedmoor. Attempting to jump through the amount of hoops necessary to try to take advantage of that extra BC with which you fell in love, is an excercise in masochism.

 

[LRShooter101]

Going back over what you initially posted, the answer may actually be right there:

“The relatively new Hornady 7mm 180gr ELD-M has a G1 of .816 and a G7 of .411 when used in a 1:7.5 twist barrel. That is staggering. To get a higher BC (in a non-solid bullet) you need to step up about 100grs to a 285gr ELDM in .338. I want to build a new rifle for myself around this bullet. The question is which cartridge to use to launch it. The only criteria I have is that the cartridge should have relatively cheap and available factory ammo”

If you want to shoot the new Hornady 7mm 180gr ELD-M, because of the ballistics, but you only want to do it with factory ammo, that is not going to probably be much of a reality.

As such, if you really want to take full advantage of that bullet, then you are going to need to handload. If you are actually willing to head down that road, then you are on the right track, and it sounds like you are focusing on what you really need to, which is running the Ballistic Calculations to see how everything is going to compare. The key is to make sure that you are always comparing an "Apple to an Apple". People get into trouble when they start chasing "hypothetical numbers" that are not going to be the norm in the real world. People will come up with a load that has an OAL which it really not practical. They will also come up with pressures and velocities that are on the ragged edge and will torch a barrel.

As pointed out above, there a number of new rounds, powders, and bullets coming out which are constantly changing the face of Long Range Ballistics. As such, it is a constant process of looking at what combinations will give you the best performance for any given set of preferred specifications.

Those specifications can include:

• Internal Ballistics: impacting recoil and barrel life
• External Ballistics: bullet drop and drift
• Terminal Ballistics: sectional density and ft. lbs. of energy
• Reloading: cost per round, component availability
• Factory Ammo: cost per round, availability
• Rifle Availability: off the shelf vs. custom
• Other: mag capability

If I was going to build a 7mm rifle today for precision long range shooting over 1,300 yards, I would go with the 7 SAUM again. However, I would build it on a long action this time to be able to maximize the OAL of the round and take full advantage of everything.

PROS

• Internal Ballistics: it would have a shorter barrel life, but it would not be a complete barrel burner. Depending on the application the recoil could be managed with rifle weight or a muzzle brake.
• External Ballistics: shooting a high BC 7mm at 2,800 – 2,900 fps would be hard to beat.
• Terminal Ballistics: it would take a large magnum to shoot a .30 cal bullet to beat those performance levels
• Reloading: not a problem for me, components are available, and the cost would be reasonable (especially when compared to a big .30 cal. mag)
• You could potently run a long action AICS mag depending on the OAL.

CONS

• Factory Ammo: would be out of the picture
• Factory Rifle: would be out of the picture

For me, the Pros would outweigh the cons. Obviously that may not be the same for you.

 

[mpk1996]

7saum built on a long action FTW!

This is the best answer for what you want. you can seat the 180s out long enough to get some powder behind it. You will have a lower recoil than the other big 7s. Factory ammo is available for those times when you want it. Good brass is readily available for hand loading. You should be able to get the 180 to around 2900-3000 fps in a long action without much issue (I ran just under 3000 fps with a 7 wsm in a short action and the bullet set much deeper than I would have liked to fit in the mag). If I were building a ELR rig right now this is what I would do.