260 In A Gas Gun Help

[wksinatl]

I'm starting load development for this rifle. I have 1k of the 140 MK's to use. I know the 142/s have a better BC but this is where I want to start. I have Varget, RE-15, and H4350 to use. I have an adjustable gas tube so I can/have shoot either of these powders and have it cycle/funxtion 100% of the time. I am really "hoping" to get H4350 to be my accuracy powder (lower psi and better dwell time).

Loading will be on a Dillon 550.

Rifle has a 24" Mike Rock/1-8" twist and wears a NightForce 5.5x-22x-56mm scope with NP-R2 reticle. I will use this rifle to compete in Tactical Matches at FT. Benning, Ga. in the Precision Semi-Auto Class. Max range will be from 500yds to 1k (depending on which range we shoot at).

You iron sight guys AMAZE me with your shooting skills with irons.

I'd like to hear some suggestions/opinions on load combos that works for you.

thanks for your time,

Keith

[michael_aos]

I've got a custom AR-10 in .260 Remington as well.

So far I've only been shooting out to 500yds, so I'm using 120gr SMK's. I have a 700P in .260 also and it gets Lapua 123gr Scenar's.

I use VV N550 exclusively for each.

Mike

[Nick Weidhaas]

I'd like to revive this old thread and see what folks are loading for their .260 gas guns and how? I'd like to know how successful you've been loading match .260 ammo on a Dillon 550b?

Thanks,

Nick-

[Nick Weidhaas]

Well I've done quite a bit of research and a 123gr. scenar or SMK seems to be a good choice. Load to 2.750 oal. for the mag. VV N550 or H4350 powder. An accomplished HP shooter who runs a .260 gas gun recommended the Wolf LR magnum primers. He said they are not harder, just a little harder. Lots of HP shooters using them I guess.

[Ken Kwiat]

I'll chime in to bump up to top and see if others have more data or comments.

I'm working up my .260 load for a gas gun (22" .260, scope will likely be a PR 3-15). OK, haven't loaded round 1 yet so take this with a grain of salt...

But, I do shoot .260 out of my bolt gun (AIAW) for LR Tac competitive shooting.

My plan is to use some of my "exercised brass". Yea, I do most of the anal brass prep stuff (primer pocket deburr, pocket uniforming, etc.). And, I have a Giraud so I'll be trimming + chamfering with it. I should add that I'm a fan of necking up .243 Lapua brass to .260 but I neck turn everything other than the few Nosler .260 pieces that I have. (An entire other topic that's covered ad nauseum on SnipersHide).

Press used: Dillon 650 will be used as a two-stage (Redding S FL sizing/depriming) x seating (no crimp planned). Haven't decided on neck tension yet but will likely build from my bolt gun experience -- nice feature of the Redding Type S dies of fine tuning with their neck bushings. COAL: 2.750" is max for AR-10 mags? OK, shorter than my AIAW/GAP barrel optimal jump to lands COAL so I'll likely start close to max (but will measure using a Sinclair comparator).

PowderCharging: this is LR thus Chargemaster to get to .1 gr. consistency. I could never get good enough consistency for the LR game from a std Dillon measure (even with some of the tweaks).

Powder experiences: I started with Reloader 17 and initially liked the results (liked, not loved). Good accuracy. SDs in the mid to high teens so not phenomenal compared to the single digits that many get with other powders.

Then, like many other early Rel17 fans, the velocity spikes with hotter temps reared it's head. So, I'm working up a H4350 load as that's what many folks consider the gold standard for .260 (4831sg as well). I won't completely rule out Rel17 for use with the gas gun as you really can get great velocity w/o pressure signs. But, I'll need to play with that variable.

Primers: CCI BR2, 142 gr. SMKs (occasionally 139 Scenars). Why heavier? Better BCs -- most of the LR Tac shooters are using either the 139 or 142s. Sure, if I can't get the velocity that I want with the heavier ones and a 22" barrel, I'll reconsider. But, from what I've seen on the Hide, there are many folks getting 2750-2800 from 22" setups.

Anyway, I'll post my results over the next month.

Edited December 20, 2010 by Ken Kwiat

[Ken Kwiat]

Not to have a monologue with myself but if others are on this path.

I found in my Pmag AR-10 mags that my COAL is limited to 2.805". Just for info, in my AIAW bolt gun, I'm running 142s at COAL of 2.871" .That gives about a .015" jump to lands. Not really planning on measuring jump to lands on the AR as I'm just going to start at mag length and adjust if needed.

Starting at 42.2 gr. and ladder by .2s up (H4350 -- the pre-eminant .260 powder).

And, as the Lapua Scenar 139 gr.'rs are slightly shorter than 142 SMKs, I'm using the Scenars to start.

Haven't fired a round yet -- too cold.

OK, I'm using my 650 as a 3-stage. As I wanted a dedicated .260 gas gun tool head set up separate from my bolt gun, I got another set of Redding comp dies. I had expected a FL resize but didn't realize that Redding still does the S Type for neck sizing and a separate body die (+ bullet seater).

Edited January 1, 2011 by Ken Kwiat

[MarkCO]

Just so you don't feel like you are talking to yourself, thanks. I'm not as far as you in load development, hope to be there this summer.

[ShooterSteve]

I'm watching this too, as I have an AR10, and I'm not really happy with it's accuracy, so I may make some changes, one of which is going to .260. Very interested in how things go for you guys. Alway eager to learn from other people's experience! Happy New Year!

[Ken Kwiat]

Thanks, Mark. Good to know you're on this path too for comparison's sake.

I believe JoeO will be working on it as well at some point so there's three .260 AR shooters in CO.

I must admit it's out of curiosity more than anything else. I really want to have a bolt and gas gun in the same caliber and get accustomed to the differences in both platforms. Plus, it's always nice to have a second gun for this LR stuff to have an option to get others to shoot a match w/o sharing a gun.

Steve: it is an interesting path. Understandably, just not as much info out there as compared to .260 bolt loads, tricks, etc. on SnipersHide. HNY to you too!

Edited January 1, 2011 by Ken Kwiat

[MarkCO]

Ken, I have a bolt and a gas gun as well.

[Ken Kwiat]

For Mark and Joe (and maybe one or two others out there):

Here's what I've found out thus far (repeated from my post on the Hide):

A 'nice day' update to gas gun .260 loads development:

A 50+ degree day in the mtns of CO (Clear Creek for you CO folk).

DensityAlt: 9420' and no wind -- rare.

Sum: the 42.6gr H4350 load is too hot in this gun. With the increase in DA over prior sessions, I was getting 2700 fps (good SDs, one at 6.0 for a 6-shot string, some SD teens) which is what I was after. BUT, too many pressure signs (very flat primers, some flow, some ex marks, one pierced primer). A different experience from my bolt gun for sure.

So, I'm backing it off .2-.3 gr. and going for 2650 fps or so. When I look at the dope table difference between 2650 and 2700 fps it really isn't a big deal.

As I run 2825+ fps with my 26" bolt gun, that difference seems significant.

Groups were decent, .5" at 100 yds.

42.3 - 42.4 gr. H4350 with 139 gr. Scenars will hopefully be the landing point.

Platform: JP LRP in .260, 22", 1:8", Pmags, Premier 3-15 Gen2 XR, Spuhr mount

Load: Lapua Scenar 139gr., 42.6gr H4350 (too hot), Win .243 necked up, turned, CCI BR2, new brass so this is FireForm

OAL: max Pmag length (2.805")

Will see how it shoots out to 600 yds soon if the weather holds.

These gas guns really beat up your LR brass. I hope I get 4-5 reloads -- that's why I'm using Win and not Lapua, btw.

[MarkCO]

Almost done with my ammo prep for the 2011 3 gun season, so I hope to wring out the first few .260 test loads in a week or so.

[Ken Kwiat]

After about 100 rounds through my .260 AR, a couple of learnings:

Load: I seem to be settling into 42.2 gr. of H4350 and achieving just under 2700 fps (keep in mind, at altitude and during the CO winter although latest chrono'ng it was pretty warm). I worked down from 42.6 gr. that was pushing it a bit with the 139 gr. Scenars. When I run dope sheets comparing 2650 to 2750 fps it's pretty minimal gains and I'm sure my brass life would suffer. Some of my primer pockets are marginally loose after the higher pressure throws. Don't want that.

So far, I'm using Win .243 resized to .260. Yea, I neck turn. I can't bring myself to devote some of my nice Lapua brass for the gas gun that likes to beat brass up.

Brass Deflector: especially with my higher pressure loads, I was getting a serious chink from the brass deflector. On my JP, it's even a plastic/delrin one. Got a SnipersHide trick of putting a little piece of velco fuzzy side over it. Seems to have worked.

Chrono: Got tired of struggling with my PACT chrono for rifle. Oehler just arrived.

[MarkCO]

Heading to the range in a few hours to chrono 40 rounds.

Thanks for the tip on the deflector, I'll put something on it.

How much gas are you running?

Edited February 19, 2011 by MarkCO

[MarkCO]

Ran my first handloads through the AR-10 with a JP .260 Upper, 21.5" barrel, today. Range is at 8000 feet and was 55 degrees and pretty windy. All new Rem .260 brass, WLP primer, chamfered and reamed brass, loaded on a RC with Redding competition seating die. Full gas shooting off a bi-pod. While I was not really shooting for groups, on 4x at 100 yards I was getting about 1" groups for 5 rounds.

I am reporting only the 2.800" OAL results below. I did have some loaded at 2.725" and 2.835" and the velocities were lower in all cases with larger SDs. I had almost no primer flow at all. I took and cut a piece of the Ergo grip material and put that on my brass deflector, worked like a charm, my brass looks almost pristine!

107 SMK over 48.0 grains of Hunter yeilded 2872 fps, SD of 8.

107 SMK over 50.0 grains of H4831SC yeilded 2846 fps, SD of 14.

130 Scirocco over 47.5 grains of H4831SC yeilded 2639 fps, SD of 24.

130 Accubond over 47.5 grains of H4831SC yeilded 2635 fps, SD of 14.

142 SMK over 42.0 grains of Hunter yeilded 2458 fps, SD of 12.

142 SMK over 46.0 grians of H4831SC yeilded 2512 fps, SD of 7.

I am pretty happy with the Ramshot Hunter and it is a small ball powder. I am going to increase the charge weights by .2 and .4 and try +/- 0.02" around the 2.800 OAL to see where I end up with some actual accuracy testing as well.

Edited February 20, 2011 by MarkCO

[Ken Kwiat]

Hey Mark,

Your results look promising. I've not considered Ramshot Hunter for .260 as I'm pretty much following the Hide pack with H4350 (with H4831SC and Rel17 in reserve). Lot's of posts over on their reloading forum.

But, your SDs look good to me with a few exceptions. Are you using a ChargeMaster or some other way for your powder throws or the dillon measure? As I'm sure you've seen me post on other threads, I've had problems getting .1 gr. accuracy in throws thru the dillon measures (esp. for the extruded powders).

Gas: I haven't touched my gas port yet. My sense is I'm a bit more open than I need to be but I was waiting to settle on my load before tweaking. My 42.2gr H4350 with 139 gr. Scenars is still just a touch hot. A few extractor marks seen yesterday at the Pueblo Pdog shoot. I have a little velocity room to spare as I am nominally shooting for 2650 fps with the 139 grs. If possible, I wanted to stay with the heavier bullets so I don't have to stock five different 6.5mm weights between the two guns.

My bolt gun vs. gas gun results were pretty dramatic yesterday but I'm really not set up fully on the gas gun yet. Not a fair comparison.

SY.

K2

[MarkCO]

But, your SDs look good to me with a few exceptions. Are you using a ChargeMaster or some other way for your powder throws or the dillon measure? As I'm sure you've seen me post on other threads, I've had problems getting .1 gr. accuracy in throws thru the dillon measures (esp. for the extruded powders).

I am using a ChargeMaster to work up the loads, however one of the reasons I am trying Hunter is because it meters perfectly in my 650. For my .30-06 loads, I might get 1 out of 10 that weighs .1 light, the other 9 being spot on. Can't say that for the H4350 or H4831SC. I just loaded another 40 that I plan to shoot on Friday.

I'm going to leave the gas full open until I settle on a load. Once I have the gas gun all tuned, then it's time to work on the bolt gun.

[MarkCO]

Next data set. 4800' 51 degrees F. All 2.800" from the 21.5" JP barrel.

107 SMK over 48.5 grains of Hunter yeilded 2963 fps, SD of 11.

107 SMK over 48.7 grains of Hunter yeilded 2978 fps, SD of 10.

130 Accubond over 48.0 grains of H4831SC yeilded 2802 fps, SD of 14.

130 Scirocco over 48.0 grains of H4831SC yeilded 2796 fps, SD of 12.

142 SMK over 43.0 grains of Hunter yeilded 2525 fps, SD of 11.

142 SMK over 43.2 grains of Hunter yeilded 2529 fps, SD of 23.

[MarkCO]

Final Data Set...I think...8000 feet, 67 degrees F. 5 shot groups, all 2.800" OAL from the 21.5" JP barrel.

107 SMK over 48.8 grains of Hunter yeilded 3084 fps, SD of 15.

107 SMK over 48.9 grains of Hunter yeilded 3060 fps, SD of 22.

142 SMK over 43.4 grains of Hunter yeilded 2659 fps, SD of 7.

142 SMK over 43.6 grains of Hunter yeilded 2689 fps, SD of 4.

Going with 48.7 grains Hunter for the 107 SMK and 43.6 grains of Hunter for the 142. Both of those loads grouped just a hair under 0.5" at 100 yards.

Now to see if those work in the 20" bolt gun...

[joeo]

Hmm. I guess I should shoot mine. I finally got ammo made and a scope on it. No excuses now.

[MarkCO]

Hmm. I guess I should shoot mine. I finally got ammo made and a scope on it. No excuses now.

Nope, join the fun.

I have 140 grain Hornady's now too. Back to working on this now that the hectic summer is over.

[dauntedfuture]

I would reccomend H4350. Thats what D Tubb used to shoot in this .260 semi when he shot a .260 SR-25. I would give RL17 if it was me. I think the semi big guns have come along way but depending on who did your barrel and the size of the gas port there might be some issues. Varget would be a little on the fast side for 142's.

[gr8horses2003]

Resurrecting this old thread. MarkCO: Are you still shooting this rifle? What loads did you settle on? Ken Kwiat: Are you still shooting the 139gr. Scenars? Have either of you had the chance to shoot the new Berger 130 Hybrids?

I am building a .260 imp 30 and am trying to get some load ideas. Will have a 27in. 1:8 twist Bartlein barrel w/ SLR adjustable gas block, extended gas tube, JP LMOS BCG and SCS. I would like to use a powder that meters well in a Dillon 550B, so Hunter is very interesting. I understand that H4350 doesn't meter that well. Is it like IMR 4064?

Any other tips would be most appreciated.

Thanks,

Harry

[Okie260]

Hello,

I just recently bought a DPMS LR in 260 Rem that I plan to use as a replacement to my 223 AR (too small for hogs) and 300 WM (too painful and a bolt so slow follow ups). I mostly shoot coyotes due to depredation and hogs due to destruction on our cattle ranch. I also just ordered a Dillon 550 after purchasing my first few boxes of $55 ammo. I plan to use the Nosler 129 grain accubonds as I want to keep the trajectory as flat as possible as I don't typically have much time to make calculations or adjustments when I spot coyotes or hogs. I saw a little older data in this thread with some 130 gr bullets. Does anyone have more data in this weight range? I got some H4831 and Reloder 17. I think I might also try to find some of the hunter based on the earlier results in this thread. Thanks.

[dauntedfuture]

Stick to 123 BTHPs, 142s were having issues in many rifles with timing and pressure curves.

Edited April 28, 2015 by dauntedfuture