Trying the Oryx chassis on the 12 FV 6.5mm Creedmoor

[CFJunkie]

I bought an Oryx chassis for the 12 FV .223 so I could eliminate the hidden magazine that made loading a chore. But the Oryx chassis allows a Savage short action to drop right into the frame without any further adjustments, so I figured that I would pull the Oryx chassis off my 12 FV .223 and try in on the 12 FV 6.5mm Creedmoor. The 12 FV 6.5mm Creedmoor has a NightForce 8-32X56mm Benchrest scope with a 30mm tube mounted on it and the large front objective required high rings to let the front objective clear the barrel. I figured it was worth a test to see if that configuration would work with the no-drop Oryx chassis. I had to lower the cheek rest on the Oryx chssis to the minimum setting to be comfortable getting my eye on the optical plane. I loaded 4 different bullets, all with loads that worked well with the factory stock and figured that a comparison of the results would allow me to decide: Whether the Oryx stock would eliminate the stock flexing I was feeling with the factory plastic stock. Provide a comfortable platform that allows a consistent set up. Improves the accuracy over the factory plastic stock. The following are the results shot in Northern Virginia on Monday afternoon, July 8th at 100 yards. Temperatures were from 74 to 76 degrees with winds from 5 to 8 mph with moderate to heavy rain for most of the afternoon. Altitude of the range is 250 feet above sea level. I was serving as range safety officer for the afternoon and normally I would not shoot when there were any shooters on the range, but the weather was rainy and everyone stayed away. With the range all to myself, I got out the 12 FV 6.5mm Creedmoor and shot 100 rounds with the Oryx chassis with 4 different loads using 4 different bullets. All rounds were shot using Lapua brass and CCI BR-4 primers. All loads were set up to match the 12th reflection time of 1.360 msec. for the 26-inch barrel with a 0.040 recessed crown. The action screws were torqued to 60 in.-lbs. per the Oryx directions prior to this session. The load description field shows the powder and charge, the O.A.L., the trim length, and the bullet exit time from the 26-inch barrel. # Grps Load Description Bullet Weight Velocity Average Median St Dev 1 2 3 4 4 IMR4451 38.9 gr 2.845 1.903 wf 1.360 * 79/74 deg. F. 60 in.-lbs. Oryx CCI BR-4 Sierra TMK #7430 130 2701 0.331 0.345 0.031 0.244 0.343 0.346 0.350 4 IMR44451 38.8 gr 2.823 1.909 wf 1.360 * 75/76 deg. F. 60 in.-lbs. Oryx CCI BR-4 Hornady ELD-M #26331 140 2666 0.337 0.334 0.052 0.284 0.301 0.357 0.394 4 IMR4451 39.0 gr 2.835 1.912 wf 1.359 * 72/74 deg. F. 60 in.-lbs. Oryx CCI BR-4 Sierra SMK #1742 142 2665 0.339 0.359 0.061 0.254 0.337 0.380 0.386 4 IMR4451 38.8 gr 2.358 1.906 wf 1.359 * 77/75 deg. F. 60 in.-lbs. Oryx CCI BR-4 Hornady ELD-X #2635 143 2658 0.335 0.327 .038 0.297 0.324 0.329 0.388 16 0.335 0.340 0.042 Comparison of Factory Stock with Oryx Chassis Factory Oryx Chassis Bullets Weight Avg. Median St Dev # Grps. Avg. Median St Dev # Grps. Sierra TMK #7430 130 0.357 0.352 0.056 31 0.331 0.345 0.031 4 Hornady Match # 26331 140 0.373 0.355 0.081 35 0.337 0.334 0.052 4 Sierra SMK #1742 142 0.304 0.306 0.045 11 0.339 0.359 0.061 4 Hornady ELD-X #2635 143 0.375 0.369 0.069 39 0.335 0.327 0.038 4 0.363 0.345 0.062 116 0.335 0.340 0.042 16 The average of the results with the Oryx stock shows a 7.6% improvement over the factory stock with the same bullets. However, I have a tendency to take a session or two to get accustomed to a new configuration before I get the most out of it, so I think it may take more than one session to see the benefits of the Oryx chassis. The Oryx chassis did eliminate all the flexing that occurred with the factory plastic stock and the platform was incredibly stable through recoil. I could hear the chassis twang a bit, almost like the sound of an AR recoil spring after the initial bang. The removal of the flexing of the factory stock was the primary reason for trying the Oryx on the 6.5mm Creedmoor.

[varget204]

Had a ?,what magazine are you using in your ORYX chassis, ? . i have 2 of the plastic 6 creedmoor 102232's, rounds set too low to feed, if you load 1 at a time no problem. Don't have a 6.5 creedmoor,do have a 6.5/284,the 120,123 grain A-max and the 120,123,and 130 ELD's shoot in the low .2's to the low .3's

[CFJunkie]

I bought one 10 round mag from MDT but found out, after it arrived, that the plastic follower and the molded top restricted the O.A.L. to about 2.830. I get the best results when I seat my Hornady and Sierra Bullets out past that.
I ordered an all-metal 5-round AI mag from Brownell's that has about 2.895 available length for O.A.L. and that was what I used for the loads I shot ( 2.858, 2.845 and 2.835 wouldn't fit in the MDT magazine).
It feeds great and drops right out of the mag well when you press the release. The MDT mag doesn't do that.

[CFJunkie]

This are the latest results of the second session using the Oryx chassis with the Savage 12 FV 6.5mm Creedmoor action on July 16^th with an 8-32X56mm NightForce scope with a 30-mm tube mounted with Burris ZEE Signature high rings. The session was shot in Northern VA at 100 yards at an altitude of 250 feet above sea level. The temperatures were quite a bit hotter than forecasted so I was fortunate to be using a powder that is temperature insensitive. The net effect a temperature variation of 10 degrees on velocity was only about 1 fps.

All the loads were shot using Lapua brass.
All bullets were loaded to achieve a 1.359 to 1.360 msec. exit time (12^th reflection) to stay under Pmax using IMR4451 powder. The jump for each load was approximately 0.020 with adjustments within 0.003 made to achieve the desired exit time.

The primers were switched to use CCI BR-4 primers with the first loads of the Sierra 142 gr SMK #1742 bullets and 140 grain Hornady ELD-M #26331 bullets. Remington 7 ½ primers were loaded for the second loads of the Sierra 142 gr SMK #1742 bullets and the Hornady 140 gr #26331 ELD-M # 26331 bullets with approximately the same loads for both sets, adjusted only for differing brass trim lengths. I planned to compare the results for the CCI BR-4 primers and the Remington 7 ½ from this session. I expect to try this again to get a larger statistical sample size.

The load description field shows the powder and charge, the O.A.L., the trim length, and the bullet exit time from the 26-inch barrel.

# Grps	Load Description	Bullet	Weight	Velocity	Average	Median	St Dev	1	2	3	4
4	IMR4451 39.1 gr 2.841 1.910 wf 1.359 * 72/81 deg. F. 60 in.-lbs. Oryx CCI BR-4	Sierra SMK #1742	142	2666	0.331	0.357	0.082	0.216	0.331	0.383	0.395
4	IMR4451 39.0 gr 2.847 1.907 wf 1.359 * 74/83 deg. F. 60 in.-lbs. Oryx CCI BR-4	Hornady ELD-M #26331	140	2670	0.356	0.333	0.0.112	0.257	0.277	0.389	0.499
4	IMR4451 39.1 gr 2.838 1.905 wf 1.359 * 76/86 deg. F. 60 in.-lbs. Oryx Rem 7 ½	Sierra SMK #1742	142	2666	0.363	0.367	0.014	0.343	0..365	0.368	0..376
4	IMR4451 39.1 gr 2.854 1.901 wf 1.359 * 78/87 deg. F. 60 in.-lbs. Oryx Rem 7 ½	Hornady ELD-M #26331	140	2672	0.355	0.344	0.048	0.311	0.327	0.360	0.420
16					0.351	0.363	0.067

To get a comparison of the factory stock versus the Oryx chassis performance, I went back to my records and compared previous results with these two bullets shot with the same powder and scope using the plastic factory stock and the Oryx chassis.

The overall average group size for the first session using the Oryx chassis with the 12 FV action, the NightForce scope and IMR4451 powder and 4 different bullets averaged 0.335 for 16 groups.

During previous sessions using the plastic factory stock using IMR4451 powder and NightForce scope, the 140 gr Hornady ELD-M bullets averaged 0.349 for 18 groups. During the previous session with the Oryx chassis, the 140 gr Hornady ELD-M bullets averaged 0.337 for 4 groups using CCI BR-4 primers, IMR4451 powder and the NightForce scope. During today’s session, the same bullets using the Oryx chassis averaged 0.355 for 8 groups with IMR4451 powder with the NightForce scope giving the Oryx chassis an average to date of 0.349 - identical to the factory stock.

During previous sessions using the plastic factory stock using IMR4451 powder with the NightForce scope, the 142 gr SMK bullets averaged 0.352 for 9 groups. During previous sessions using the Oryx chassis with the 12 FV action, the 142 gr Sierra SMK bullets averaged 0.339 for 4 groups using CCI BR-4 primers and IMR4451 powder with the NightForce scope. During today’s session, the same bullets and the Oryx chassis averaged 0.347 for 8 groups with the same powder and scope giving the Oryx chassis an average to date of 0.345 – slightly better than the factory stock.

There were only 4 groups for each of the two bullet loads with the two types of primers. The CCI BR-4 primers averaged 0.343 for 8 groups and the Remington 7 ½ BR primers averaged 0.359 for 8 groups. Unfortunately, the sample size is too small to make any final conclusions but the BR-4 primers performed slightly better so far. That is the opposite of the preliminary performance of these two primers to date on the 12 FV .223 with 77 grain SMK and TMK bullets.

[CFJunkie]

Here is the Flat Dark Earth version of the Oryx chassis that I bought for the 12 FV 6.5mm Creedmoor.
I like the look of this version more than the green version I have on the 12 FV .223.


The high rings on the NightForce 30-mm tube are just high enough to get a comfortable cheek weld with the adjustable cheek rest set at its lowest setting.


I bought the sling swivel from Oryx to mount the Sinclair F-class bipod on the 12 FV .223 chassis, but I bought a cheaper swivel for the 12 FV 6.5mm Creedmoor from Brownell's and it

worked just as well.

[DesertDug]

Looks as good as you shoot them.

[CFJunkie]

Hopefully, the results improve with this stock as much as the group sizes improved on the 12 FV .223 with the other Oryx stock.
It took me a couple of sessions with the new set up until suddenly the groups got smaller.

I expected quicker improvements with the 6.5mm Creedmoor because the factory stock flexed so much under recoil.
The Oryx chassis just about eliminated the flex but I can hear the chassis 'twang' under the stress.
It reminded me of the recoil tube noises shooting an AR.
I guess the 'sound' is from the action bolts and recoil lug are straining against the aluminum frame.

[CFJunkie]

Here are the results of the latest session with the 12 FV 6.5mm Creedmoor mounted in the Oryx chassis using the 8-32x56mm NightForce Benchrest 30mm tube scope with Burris ZEE Signature high rings. The session was shot on Saturday morning, July 27^th, in Northern Virginia at 100 yards at an altitude of 250 feet above sea level.

All the loads were shot using Lapua brass. All bullets were loaded to achieve a 1.361 msec. exit time (12^th reflection) to stay under Pmax using H4350 powder and CCI BR-4 primers. I finally got some H4350 powder and I wanted to see how it would shoot in this rifle.

I have much more data using CCI BR-4 primers than Remington 7 ½ BR primers so I decided to start with the CCI BR-4 primers that have the most data to easily compare results.

The jump for each load was approximately 0.020 with adjustments within 0.003 made to achieve the desired exit time to account for variations in trim length.

The load description field shows the powder and charge, the O.A.L., the trim length, and the bullet exit time from the 26-inch barrel as well as temps expected and experienced, torque, stock, primer and pressure (from QuickLOAD).

# Grps -------Load Description -------------Bullet----- Wgt. – Vel. -- Avg. – Median – St Dev –-- 1 -------- 2 -------- 3 ------ 4 ---
4 ---- H4350 40.9 gr 2.832 1.907 -- Hornady ---- 147 – 2649 -- 0.286 – 0.282 --- 0.040 -- 0.241 -- 0.271 –0.293 – 0.337
--------- wf 1.361 71/71 deg.F. --------- ELD_M
--------- 60 in.-lbs. Oryx CCI BR-4 ------ #26333
4 ----- H4350 41.5 gr 2.856 1.905 –- Sierra -------- 142 – 2685 – 0.341 – 0.329 –-- 0.027 – 0.324 – 0.325 – 0.333 – 0.381
--------- wf 1.361 75/74 deg. F. ------- SMK
--------- 60 in.-lbs. Oryx CCI-BR4 ------ #1742
4 ------- H4350 41.3 gr 2.844 1.902 – Hornady ---- 140 – 2688 – 0.320 – 0.326 –-- 0.049 – 0.254 – 0.322 – 0.330 – 0.373
--------- wf 1.361 78/77 deg. F. ------- ELD-M
--------- 60 in.-lbs. Oryx CCI BR-4 ------ #26331 -------------------------------------------------
------------------------------------------------------------- Average -- 0.315 – 0.325 --– 0.043


H4350 powder averaged based upon the performance of the 147 grain ELD-M bullets but all three bullets managed to average better than the overall average through the last session.

Up until today, IMR4451 led the performance results with an average of 0.355, but since the H4350 results were with the Oryx chassis, it may be more meaningful to compare the IMR 4451 results shot with the Oryx chassis to the H4350 results. Although this is a small sample, there appears to be a marked difference (7.6%) in the performance of the powders favoring H4350. It looks like there will have to be more testing with H4350 powder to see if it will continue to show that improved performance.

	H4350	IMR4451
140 ELD-M	0.286	0.346
142 SMK	0.341	0.335
147 ELD-M	0.320	-------
	0.315	0.341

[LuvmyLRP]

CFJunky: I enjoyed your read. Shows a lot of time and work invested. I would like to ask how you got such good groups with the 77 grain SMKs. I have two mod 10s with Boyds target/varmint stocks. They are both factory 1/9 twist and stop at 69 SMK. They won't even think about shooting 68 or 75 grain Hornady ELD ms. The 69s will shoot consistently under 1/2 moa, but heavier just drops off the cliff. They are both due for rebarrel and I'm thinking about a 1/12 and maybe a 1/7.5 to do light and heavy bullets. They just won't do it now.

[CFJunkie]

LuvmyLRP,

I should also post this answer on my 12 FV .223 thread, but I'll answer your question one here on the 12 FV 6.5mm Creedmoor thread.
Actually, it is hard for me to believe 77 gr bullets will even stabilize in a 1:9 twist, too!
Everything I have heard for years and years says they won't, and even Sierra says they won't, but when I tried them, I was astounded by the results.
I never expected the 77 gr SMKs or the TMKs to group at all, and they wound out shooting better than any other bullets I have shot from 50 grains to 70 grains with this rifle.
The 69 SMKs and 69 TMKs shoot well in the 12 FV .223, but the 77 SMKs and TMKs shoot even better.

Since I started shooting 77 grain bullets, my overall average improved from 0.362 to 0.320.
My average with the 77 grain SMK and TMK bullets is 0.285.
I can't explain it, I can only report the results.

However, I expect it has a lot to do with loading the 77 gr bullets out to 0.020 off the lands.
The Sierra recommended seating depth for both bullets is 2.260.
I am shooting the SMKs at 2.290 to 2.303 and the TMKs at 2.325 to 2.345 to get the best results with my chamber depth.
The TMK tips make using O.A.L. a bit more complicated because the tip adds at least 0.050 to the O.A.L.
I questioned Savage about how they came up with the 2.260 recommendation and asked it the limits of an AR magazine had anything to do with it.
The response from their rep was that the AR mag limits probably had something to do with it.

The 77 SMKs averaged 0.395 when the O.A.L. was 2.280 or less.
The same powder and bullet averaged 0.251 when the O.A.L was between 2.296 and 2.301.
The 77 TMKs averaged 0.275 when the O.A.L. was between 2.330 and 2.345.
When I moved the 77 TMK O.A.L out 2.350 to 2.353, the O.A.L was 0.330.
When I moved the O.A.L. back to 2.293, the 77 TMKs averaged 0.289.

I think finding out where to seat them makes a difference but I honestly can't explain why they even stabilize.
It is pretty clear to me that with this particular rifle, the position of the bullets re the lands is pretty important.

[charlie b]

I don't know why either, but the 77 SMK's shoot best in my .223 Axis HB as well (also a 1/9 twist).

[hamiltonkiler]

Bullet ogive.
Not all bullets are created equal. The US navy special forces use bullets for a reason.
Same with hunting. Public, “can’t hunt with a match bullet.”
Shoot a deer with a matchking. Serria. Tell me how it does compared to other .224 bullets.
Cheers



Sent from my iPhone using Tapatalk

[charlie b]

The "surprise" part is that Sierra prints on their 77gn MK box, 1:8 twist or faster.

Why would I use a match bullet for hunting? And I'd never use a .224 for deer unless it was a pure survival issue.

[CFJunkie]

charlie b

The SMK and TMK are both match bullets and I wouldn't use them for hunting either, especially on deer. The match bullets have thicker jackets and don't expand like a hunting bullet.
It is illegal in some states to shoot deer with .224 bullets of any type, match or hunting bullets.

Sierra recommends an O.A.L. of 2.260 for both the 77 gr SMK and TMK.
The SMK is more accurate out around 2.290 to 2.300 and the TMK is more accurate out around 2.340.

I asked Sierra why they recommended an O.A.L. so short for such long bullets when they shoot more accurately seated out 0.040 and 0.080 further respectively.
I asked if the limited AR magazines had anything to do with their recommendations.
Their rep responded by saying "it might have been a consideration."

I agree with hamiltonkiler that their higher ballistic coefficient (related to their weight, bullet length and the secant shape of the nose) has a lot to do with their unprecedented stabilization but, like charlie b, I am amazed that Sierra doesn't seem to be aware of it.
The 77 gr Sierras have now become a mainstay of my 12 FV .223's loads.
I will now try the same loads in my old CZ 527 Varmint bolt action that also has a 1:9 twist and see if they do as well in a 24 inch barrel.

[LuvmyLRP]

CFJunky: I'm glad that it was your post that I referenced and that I am Not losing it. Something happened when I logged in. I haven't tried the 77 SMKs, but now I'm going to. 69 SMKs are my go to accuracy bullet for .223. Guess I should try fiddling with the jump a little more. I show the chamber depth for the 69SMK in my mod 10 as 2.0380 with a Hornady 2-22 insert and I usually load it .020 off the lands. I don't know what the oal is. If it won't load in the mag, I check it. My 12 LRP 6.5CM eats about any OAL you want in the mag with room to spare. On the other, my RPR 6.5CM is limited by the mag to very short OAL. That's with a Magpul mag, but may be different with a metal mag. It's hard to single load the RPR because of the bolt hold open on the last shot. You have to really shove it hard to single load. Maybe I can find a ramp insert. With the chamber and mag combo on the RPR, it's hard to work too much on jumps. I'll say it again, LUVMYLRP. Trying to decide on which new barrel for it, but that's another thread. Thanks for the data on the .223 and 6.5. Call me crazy, but I love the LRP factory stock. I just can't get used to space gun stocks. I tried an A2 stock on my RPR, but It just didn't feel right. I would like to try the Magpul butt stock, but no one here is using one for me to try.

[charlie b]

I was in the same boat as you for a long time. Max 69gn SMK's. I read a post in here about someone who competed at 600yd with 77gn SMK's so I tried them. Since they worked I kept shooting them. I suspect that what Sierra is referring to is 20" AR barrels. The extra velocity and spin rate we can get with a 24" barrel may be the difference. I also thought it might be cause I shoot at 5000ft elevation but CFJunkie is nearer to sea level. And I get good results at 40F as well as 100F.

FWIW, I have been loading my .223 77SMKs at the recommeded length of 2.26". Just never messed with it. As is I get consistent 0.5MOA groups out to 300yds. CFJunkie is at another level better than I am.

I am going to try the longer length to see how much difference that makes. I have a 'control' batch loaded now so I can compare.

Sorry for the extra off topic.