70gr RDF in an AR

TxSteel

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Mar 22, 2018
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#1
What powders are working under these? I am looking to squeeze out as much velocity as i can get. Looking at the Hodgdon data, Varget and H4895 might get me there. What powders am I missing?
 

Greg Langelius *

Resident Elder Fart
Aug 10, 2001
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#2
I use Varget and let it go at that.

There's a good reason why it's so popular. It works in all my loads from 50gr to 75gr; it's just very versatile.

I am reducing my powder choices. I'm down to Varget for all my 223's, IMR-4064 for all the larger .30's (.308, 7.62x54R, and .30-'06), H-4350 for the .260, and IMR-4198 for the 7.62x39 and .30BR. I'm putting the x54R and the .30BR in the back of the cabinet these days.

If I return to the .280, I'll be using H-4350.

I have some H-4831SC left over and may try it with the 143 ELD-X in my 28" .260, it really should be a better powder for that application, and is more often available than H-4350.

Greg
 
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Likes: natdscott
Jun 13, 2008
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#5
Well if Greg is going to ETA and elaborate, then I will too.

Either Reloder-15 or Varget will get you 98% of what a heavy .223 can do. Typically, the 65-73 grainers are slightly better suited to Varget, where RE-15 is slightly better suited to 70-80 grainers. The reality is that either one works really effin' well from 70-80 grains.

Only for the last 50 yards or maybe 100 yards do you need something like 2000-MR, and if you were concerned with that kind of range, you'd not be asking about bullets whose weight starts with 7.

So yeah. Either of those.
 

TxSteel

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Mar 22, 2018
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#6
Well if Greg is going to ETA and elaborate, then I will too.

Either Reloder-15 or Varget will get you 98% of what a heavy .223 can do. Typically, the 65-73 grainers are slightly better suited to Varget, where RE-15 is slightly better suited to 70-80 grainers. The reality is that either one works really effin' well from 70-80 grains.

Only for the last 50 yards or maybe 100 yards do you need something like 2000-MR, and if you were concerned with that kind of range, you'd not be asking about bullets whose weight starts with 7.

So yeah. Either of those.
I've already limited myself at an 18" barrel. I am attempting to make up the lost velocity in barrel length with a lighter bullet, which is why i've decided to try the 70gr Nosler RDF. I have Varget and CFE223 on hand, 2000MR is another powder I am interested in.
 
Jun 13, 2008
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#8
Does the 70 RDF work well at magazine length? What velocity are you getting?
Thanks
It's brand new. There's relatively little data for it, but reading BETWEEN the lines, I doubt that it will jump quite as well as a true mag bullet like the 69 SMK or the 73 Berger. That being said, it IS stated to be a "compound" ogive, so they may have hybridized it so that it works okay from mag. Really, I bet they have: with few exceptions, you're committing reloading product suicide if you bring out a .224 that won't work from an AR magazine.

Without knowing more about it...like bearing surface...it's hard to say how much power it can take, but I'd be surprised if it doesn't go at least as fast as a 69 SMK...the 69 is a longer-bearing surface design, at least for that weight class.

For figuring, if you have an 18" tube, plug in 2,800.

-Nate
 

TxSteel

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Mar 22, 2018
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#9
I guess I will just have to pick up a box and see what happens. I will start with Varget since i have it on hand. Nate I was hoping there was some way i could squeeze 2,900fps out, but from your experience i should lower my hopes by atlease 100fps?
 
Jun 13, 2008
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#10
MR might do it, but barrel life will probably be reduced.

Don't forget...damned small lugs on these rifles. If you DO decide to push max, go no more than 0.1 at a time, and use a high quality bolt.
 
Jun 13, 2008
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#11
...and shoot, I could be completely wrong.

It MAY have a really short parallel, and take another 1/2 grain. You might get 2,850-2,900 easily.

But I took 50 fps off a normal 20" 69SMK load. Probably aggressive, but I prefer to plan conservatively.
 

FishDr

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Apr 10, 2014
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#12
Aren’t these rdf’s more of a “VLD” type bullet shape? Me thinks they might be a pita to run mag length? Am I wrong?
That is why I asked …
Just as a data point, I have an 18” Barrel that gets 2900fps using PP-2000-MR and 69 SMK. With that velocity, I can’t get the usefulness of higher BC using a 77 because it’s too slow. If the 70 could be run from a mag with similar velocities as the 69 … OH JOY! But being closer to a VLD style, I wonder if it takes too much case capacity and therefore compares more with the 77s. Others experience is appreciated.
 

TxSteel

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Mar 22, 2018
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#13
...and shoot, I could be completely wrong.

It MAY have a really short parallel, and take another 1/2 grain. You might get 2,850-2,900 easily.

But I took 50 fps off a normal 20" 69SMK load. Probably aggressive, but I prefer to plan conservatively.
Well Nosler advertises the 70 RDF OAL at 0.965, JBM has the 69SMK listed at .900 and the 77SMK at 0.994.
 

padom

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Mar 13, 2013
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#15
Myself and a few others on here reviewed 70 RDF's a while back in 20" AR's in 1:7 Bartlein and Kreiger barrels and they shot like crap. Seating depth testing was done and couldnt get them tightened up testing within max mag length of 2.31 in ASC mags.

Now, I had so many on hand I recently tested them in my 26" 1:7 bolt gun barrels and they shot tiny little groups between 2950-3050 with Varget and H4895...

My conclusion, they like to go fast.
 
Likes: demolitionman
Jul 11, 2010
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#16
What kind of jump were they making in that bolt gun?

Everything I've read on these is that mag length in an AR doesn't yield good results with the 70gr RDF, unfortunately.
 

TxSteel

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Mar 22, 2018
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#17
I got cold feet on the RDFs, taking what Padom said and my own experience with the 175 RDFs. I bought a box of 73gr ELD-M instead.
 
Feb 14, 2017
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#22
I tried the 70 RDF's when they were new. I managed 2850fps from a 16" and 3050fps from a 22" with TAC, about 100-150fps slower with 8208 and CFE. Lengths from 2.26-2.35" all shot like butthole.
 
Jun 13, 2008
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#25
More so than the 77smk? Any benefits to those over the 77smk in a fast twisted 18" barrelled ar15?
Tex is on it, mostly. If you are looking at using a match bullet for killing things, and you feel that speed is the need, then maybe the 77 isn't the best choice. The military disagrees, and so do I, but that may not be right.


My experience has been that the 77 SMK, while it cuts wind appreciably better at 300+ yards, does not group as tightly as the other two. It's always been little narrow groups that are 3/4 Minute tall. Pisses me off.

It's a great bullet, and I used it despite that grouping thing because of the BC, but I've just never seen it REALLY shine.

My personal X-count record on the 300 yard slow fire target (2.85" X-Ring) is still at 12, and the 69 SMK holds it.

-Nate
 
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padom

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#26
Tex is on it, mostly. If you are looking at using a match bullet for killing things, and you feel that speed is the need, then maybe the 77 isn't the best choice. The military disagrees, and so do I, but that may not be right.


My experience has been that the 77 SMK, while it cuts wind appreciably better at 300+ yards, does not group as tightly as the other two. It's always been little narrow groups that are 3/4 Minute tall. Pisses me off.

It's a great bullet, and I used it despite that grouping thing because of the BC, but I've just never seen it REALLY shine.

My personal X-count record on the 300 yard slow fire target (2.85" X-Ring) is still at 12, and the 69 SMK holds it.

-Nate
I have to disagree. Ive shot 10's of thousands of 77smk with bughole accuracy out of my WOA's and Rainier Ultramatch's with 8208XBR. Most accurate AR bullet Ive shot. I have recently been shooting the 73 ELD which is also very accurate and fast but that 77smk just always produces tiny little groups.


20" WOA SDM 1:7


77smk - 8208XBR OCW






77smk - 23.6g 8208XBR Seating Depth Test






23.6g 8208XBR - 77smk - 1.858" Ogive - 4x5


 
Likes: demolitionman
Jun 13, 2008
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#27
Padom, are those mag length?

I am rusty on how long my B-O measurements would be for those bullets. On the long side, it's never mattered, since I have to be under 2.255".
 

FishDr

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Apr 10, 2014
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#29
Mag length for sure. they are around 2.488 coal I think
That must be a bolt-gun mag length or a typo. How about your WOA barreled AR? I used your recommended load and it was very accurate, but velocity dropped off enough that the dope on the 69smk was about a wash so stuck with those for $$ savings.
 
Jul 11, 2010
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#32
Haha, Pardom, I run the exact same load. A 77gr SMK over 23.6gr of 8208XBR at 2.245" OAL.

If looking for more velocity without losing too much BC you can look at the 69gr TMK. Sierra reports it has the same BC as the 77gr SMK and my buddy used them last weekend in a DMR match out to 720yds with great effect from a 1:7 twist 18" AR.
 

Kiba

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Jan 13, 2011
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#33
Played with the 70 RDFs a while back in my JP with H4895, varget, and AR comp, all loaded at mag length.

All loads had good velocity and low SD, found some promising nodes. Unfortunately none came close to grouping as well as the good old Sierra 77 MK. Same with the 73 ELD-M, couldn't get it to group as well as the old Sierra 77.

I was really hoping the RDFs or ELD-Ms would work because of the velocity gain and BC advantage, but as of today I'm still shooting the Sierra 77. I've had good luck with the 69 TMK also, better groups than either the 70 RDF or 73 ELD at mag length, but not as good as the 77 MK.
 
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Jun 13, 2008
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#34
I'll pile a little more on. I tried the 69 TMK, and for mag length loads, it was so rough for something like 90 rounds that I kept one for the memory and tossed the rest in the trash.
 

TxSteel

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Mar 22, 2018
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#35
I have some 73gr ELD-M stuffed on top of varget to run over my chronograph hopefully tomorrow. These bullets seem to be a mile long, and they sure do eat up alot of case capacity. I think i'm going to try to track down some 2000MR, and see what kind of velocities i can get and go from there. The 73gr Bergers have me interested, but I am not sure what velocities I will be able to see from them.
 

Rudy Gonsior

Breaker of Things
Jan 3, 2018
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#39
Picked up some 70gr. RDFs earlier this year after thinking about getting in to service rifle and have been trying to research a good load but nothing solid pops up. Everyone seems to get real finicky results. Yesterday I dicieded to say fuck it and go with my gut. I primed up som Lapua cases with CCI 400s and proceeded filled the cases to the neck with Varget (25.7gr.) knowing that Varget likes to shoot compressed. After that I jammed the RDFs to whatever mag lenght is for P-Mags (2.260"-ish).

I cranked 5 rounds over the chrono in my shop and got an average of 2840 FPS and an SD of 12.5 FPS from my WOA 20" SDM barrel. After that I walk out to the 100 yard range out back and cranked off 5 more from the sling/prone for accuracy, and printed a nice 1 MOA on steel. Giving the Leupold SPR reticle is just about 1 MOA wide, I'm going to call that good for now. I've got a Service Rifle match tomorrow so we'll see how they hold together but so far so good.
 

Rudy Gonsior

Breaker of Things
Jan 3, 2018
248
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Maine
ridgelineshooting.com
#41
Alright, went and shot the beginners service rifle match today with 70gr. RDFs and they did well...me not so much. Standing at the 200 was rough, shot an 87 but that was all me and no coffee, every shot when right where I called it. Rapids at 200 and 300 were good, shot 98 and 98, both groups were right at 1 MOA wide and about 1 MOA in height and shaded a little high in the 10 ring. Prone at 600 was complicated with a switchy tall wind and end up somewhere around 180-185 (I had to bail before the official results) but the total vertical was right at 1 MOA. Overall the load is a solid 1 MOA performer, which is not bad for 10 rounds of load development and zeroing. At nearly half the price of the 77SMKs I'll probably stick with them through the season. I'm going to swap out the 4x for a NXS 3-15x and try my hand at an F-Class match, should get me some more precise data than the sling.
 
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