Sierra 120 Tipped Gameking

[Legionnaire]

My first test loads with this bullet will be over TAC, or Accurate 2520, as that's what I have on hand.

[koden]

I've loaded up 3 different powders so far. All in 3-4x fired Hornady brass.

PPV: Seating to 2.260, loaded up to 29.6g. Mildly compressed at max load. Probably no compression if I seated to 2.280.

CFE 223: Seated to 2.260 up to 29.6g which was mildly compressed then seated to 2.280 up to 31.2g which was compressed but not a huge amount.

ARComp: Started at 26 and stopped at 27.1 which was very compressed, all seated at 2.280

I dont think the stick powders will do good in this round if your looking for speed. Too much bullet intrusion as others have noted. Its longer than the 123smk!

[grayfox]

Couldn't wait!
Loaded up some 3/load in CFE to do a small ladder, 120 tgk's.
30.3, 30.6, 30.9, 31.2 All were 2.280 except the 31.2, which went 2.290.
ST-1x brass, cci 450 primers. over my mgsp. chrono to 100 yds.
Shot them through my 22" pref bbl, howa mini. Great barrel by the way!

30.3 - 2499
30.6 - 2515 this was the prettiest looking group.
30.9 - 2538
31.2 - 2562. This group started to have some stiff bolt lifts.

SD's don't mean much to me as this was only 3 shots/data point. But the 30.6 was the best SD number...

All the brass looked fine, I'll look at them more closely a bit later.

[ATTACH=CONFIG]20028[/ATTACH]

[Konocti's Wigwam]

What about 30.3 ??? That group like good to me.

KW

[grayfox]

true. but.
My model for node estimating says more like 2515-20 for this 22" barrel.
Grt estimates more like 2535-40 but that has not been the actual behavior so far for the barrel.
2525, 2520, 15 the lower edge.
I'll probably get around to testing some lever with it, it estimates up to around 2600.
I don't always go for the absolute max, but for a good MV that's on or close to a node.

these were only 3 shots per load, so I'm not making a lot of group size judgments yet.

[Bobke]

Grayfox-Your points of impact on the 30.3/30.6/30.9 were all awfully close, suggesting a node. Have you thought about playing with seating depth to see where you optimum accuracy lies. I have four sets of six rounds using CFE, Lever, PPV and AR Comp set at 2.280 OAL to start my testing. Look forward to more of the collective test results.

[grayfox]

Grayfox-Your points of impact on the 30.3/30.6/30.9 were all awfully close, suggesting a node. Have you thought about playing with seating depth to see where you optimum accuracy lies. I have four sets of six rounds using CFE, Lever, PPV and AR Comp set at 2.280 OAL to start my testing. Look forward to more of the collective test results.

Looks like that, but there's 2 reasons why I don't typically trust that:
1. These shots were with a magnetospeed, which does alter the point of impact, although in theory it should do all shots the same way -- sometimes it doesn't.
2. I don't trust my own steadiness enough to rely strictly upon impact points on paper, and these were only 3 shots each anyway. I'm not as rock-solid as some guys on here.

My method uses a different approach, based on Chris Long's OBT theories (appeals to the eng-geek in me).
1. I shoot a few over a spread of charges to establish a chrono-MV ladder vs charge, graphically. If the result is relatively linear then it tells me the powder/combo could be a useable one. (sometimes I have gotten pretty zig-zaggy graphical results from a powder on this step, so I usually move to another powder). I define a "well-behaved" powder as one that shows "pretty much linear" increases in MV for linear increases of powder charge, over a reasonable charge-volume case combo. That's what powder should do anyway!
2. I will shoot a narrower charge spread, with 4-5 per charge, looking for a node close to a mechanical one predicted by Long's theory (longitudinal pressure wave-travel). For a 22" barrel and 120 class bullet in Grendel, this usually means 1 is close to 2520 fps give or take.
3. I pick one from this narrower spread, close to the node, which usually has the lowest or close-to-lowest MV spread in SD. Then shoot these while changing OAL length to find the best group.
4. Then I can zero that group-charge for 100 yds.

[zholley]

The listed BC on the Sierra website remains .466 and they are currently showing in stock if anyone is interested.

I've got some loaded up over TAC and CFE223 and I'm hoping to get them shot this weekend. I'd have to look at my notes, but I did run out of room working to the max load for CFE223. I was definitely compressing powder and then began to have trouble reaching my seating depth. Obviously, I will shoot with caution working through those and I'm worried I may end up pulling some bullets rather than shooting them.

I feel fairly confident in getting good results with TAC either way. If so, I'll load up 50 and hunt with those the next few hunts.

[Popeye212]

Got my 300 today

[grayfox]

Comparing the 123 MK from JBM bullet length values to this new 120, seems the 120 tgk is about 0.012" longer, 1.295 and 1.307 (my measurement on the tgk). So, not considering if the boat tail dimensions throw us off or not, if you load the tgk a bit longer, say +0.012 (ie, 2.272 cp to Sierra's listed 2.260), you should be able to reference the Sierra load listings for that 123 as a guide. I'd expect the actual MVs to be 20-30 fps faster than the 123, but need to factor in any delta's from your barrel to the sierra test barrel.
Also haven't looked lately but I'll bet there is some load data for the 123 smk in the Grendel handbooks too.
So couple of resources there to consider.

[Popeye212]

I read in the Sierra book and recall from elsewhere to use the 123gr data which I have been using for the ProHunter and the match 120.

[koden]

I loaded up 3 more powders for testing this weekend. All of these were loaded to 2.280 and powder was settled in case before seating bullets. Hornady 3x fired brass.

Leverrevolution from 28 to 31.2 (same as CFE) Compressed at max but not bad.

H4895 from 25 to 27.4. slight compression started around 26.6 with 27.4 being pretty compressed but not hard to seat and COAL has not grown since seating. No deformed ring around the nose from seating.

8208 from 25 to 27.4. This powder actually fit well. Its slightly smaller than 4895 and arcomp. 27.4 was the max listed for the 120smk. It was just slightly compressed at max load.

[Bobke]

Not enough time to focus on accuracy, just grabbing data for the record. All in Federal brass, 205M primer, 2.280 OAL, 20” Proof CF barrel. All 6 shot samples. 60d, 75+ RH.
27.0 AR Comp 2547/6.4 SD
31.2 CFE223 2540/26.8 SD
31.2 Lever. 2576/11.6 SD
29.0 PPV. 2532/12.5 SD
Somewhat predictably, ARC, Lever and PPV showed some promise at 100yds. More testing required before a definitive result with my platforms.

[Jake TN]

Ran to the range real quick to to find a quick load for hunting. Didn’t retrieve all targets. Loaded TAC at 26, 26.4, 26.8, 27.2. Don’t think anything was compressed. I use a Redding seating die and don’t want to damage it. No signs obvious signs of pressure. Use a suppressor, so I will examine again once the brass is clean. Everything shot around an inch or under. Pleasant surprise do to the length of the bullet. Chronograph was not available at the range. I was messing with the gas block and had some magazine issues, so the groups could have been better. Definitely has the potential to be a 300 yard + hunting bullet. Will post an update when I have some terminal performance in meat. Thanks to everyone posting your data on this.

12.5 inch Lilja
Suppressor
100 yards
1-4 vortex PST
Adverse sun condition

Just realized I have no idea how to post a picture on here. Tried uploading one from my iPad and it wouldn’t take. Sorry folks

[Timitus]

I made a quick load up for deer season that started for me today. 27.5g of imr 4064 gave me a 5/8 group with an average 2450 fps. While I didn't get a deer today I did bring home some game.[ATTACH=CONFIG]20033[/ATTACH]
35 yard shot. DRT. The 120g TGK was a complete pass through after taking out it's neck. Lol
I hope for something bigger tomorrow.

[VASCAR2]

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[Jake TN]

Ran to the range real quick to to find a quick load for hunting. Didn’t retrieve all targets. Loaded TAC at 26, 26.4, 26.8, 27.2. Don’t think anything was compressed. I use a Redding seating die and don’t want to damage it. No signs obvious signs of pressure. Use a suppressor, so I will examine again once the brass is clean. Everything shot around an inch or under. Pleasant surprise do to the length of the bullet. Chronograph was not available at the range. I was messing with the gas block and had some magazine issues, so the groups could have been better. Definitely has the potential to be a 300 yard + hunting bullet. Will post an update when I have some terminal performance in meat. Thanks to everyone posting your data on this.

12.5 inch Lilja
Suppressor
100 yards
1-4 vortex PST
Adverse sun condition

Just realized I have no idea how to post a picture on here. Tried uploading one from my iPad and it wouldn’t take. Sorry folks

Photos

[koden]

Went to the range today and shot a bunch or powders.

18" John Benjamin barrel with .264lbc chamber
Magnetospeed chronograph

Factory Hornady 123 eldm ammo measured 2391 average of 5 shots which I thought was pretty low velocity even for my 18" barrel and the SD was up around 20. Im wondering if my magnetospeed was having issues today. I may have set it too far away from the bore. Some of the velocities below seem pretty low for the powder.

LVR: 28gr 2278 up to a charge of 31.2gr 2532
CFE223: 28gr 2231 up to a charge of 31.2gr 2441
ARComp: 26gr 2310 up to a charge of 27.1gr 2418
PPV 27gr 2308 up to a charge of 29.6gr 2436 Light ejector swipe on the max charge.
H4895: 25gr 2216 up to a charge of 27.4gr 2441
8208: 25gr 2175 up to a charge of 27.3gr 2401

Other than the max load of PPV there were no pressure signs. I was only shooting for speeds so no accuracy but LVR rounds all went into a pretty good area even though all rounds were different charges.

[zholley]

Timitus, I'm not sure I'd call that a pass through! Little hard to tell from the picture considering the head is just about gone, but I would say that it certainly expanded!

[Timitus]

I harvested a doe yesterday. Here is a break down of how the Sierra 120g TGK performed. The load was 27.5g of IMR 4064, COAL of 2.280 at 2450 fps average from my 22" barrel Ruger American. The doe was shot at 30-40 yards. It was facing the right of me slightly quartering away. Shot entered just behind the right leg. It ran 10-15 yards and piled up. The bullet was a pass through with no bones destroyed. Passed between ribs on both sides of the doe. I found the right front shoulder broken but could see no visible reason. When she was running away after bullet impact I didn't notice her leg not working correctly. The bullet did fragment on impact as I found a couple of 1/8th or smaller pieces. It is possible that I will find more in the broken shoulder later. There was no lung damage that I could find.
[ATTACH=CONFIG]20040[/ATTACH] Bullet entry.
[ATTACH=CONFIG]20041[/ATTACH]Bullet exited the chest and passed through the off side elbow.
[ATTACH=CONFIG]20042[/ATTACH]Bullet path through the heart.
[ATTACH=CONFIG]20043[/ATTACH]Bullet fragment damage to heart.