Sierra Gamechanger bullets.

Cohunt,

Thanks for a fairly comprehensive test. Although I'm a died in the wool fan of Sierra and have always looked to them for the real truth in bullets and their accuracy is always excellent, I'm still very impressed that the Sierra Game Changer did as well as it did with terminal performance.

I had already ordered some of them recently and they'll be here Tuesday if UPS does their job.

Another bullet/cartridge combo I was very impressed with was your 9" barreled 300BO! Holy crap! Great penetration for essentially a glorified pistol. The much maligned and often disrespected 300BO impresses again. Is the accuracy good with this and is it from an AR platform? Handloads?

Dirt isn't just dirt folks... Even a moderate amount of clay in a backstop can make it waaaay tougher on bullets if it's dry. To say how a bullet that was dug out of a dirt backstop performed it's probably more meaningful if you discuss the approximate composition of the "dirt".

I used to do a fair amount of shooting at a private range on a hunting lease that was near the Gulf of Mexico here in Florida and we had one range that had an old sand dune on it. It was composed mostly of very light colored beach type sand typical of the panhandle of Florida beach areas.

We loved to dig out bullets we'd fired into that backstop and one of the few bullets that retained any lead was the good ole Nosler Partition. It may be very old technology and only have a "cough" lead tip but they have always been reasonably accurate with MOA groups at 100yds the norm from a well tuned rifle. That tough lead core at the rear of the bullet never failed me even once even in sand backstops.

My go to deer hunting rifle for many years was a Remmy Model Seven in 308 Winny and my go to load had used Reloader 7 and a 150gr Nosler Partition. I shot everything from coyotes to deer with them and never even once had anything less than DRT perfect performance with them on game.

I'm still looking for a bullet that matches the Partition for toughness and reliable, no excuses, instant kill from any angle even through tough bone. The Nosler AccuBond, although almost as accurate as their Ballistic Tips, never impressed me with their terminal performance and my biggest disappointment with them was that they tend to wander after penetrating that first layer of deer hide where the Partitions always retained their original flight path and punched right through.

By the way... I was never impressed with a bullet's weight after penetration on game. The Nosler Partition almost always sheds the front part of the bullet so retained weight is minimal but they kill like the hammer of Thor. Even the few Ballistic Tips I recovered had very little weight retention but they also kill very well with broadside shots.

ADH, the 300 holds 1.25moa at 100y witj factory Barnes ammo--i usually get 3 out of 5 under 1moa.

This test was not done to try to persuade people 1 way or another that the SGC is good or bad, same thing witj the eldx

It was simply done just to get some comparative data to help me and others make their own decision if they want to try the new bullet construction or not

LDHunter in post #127 you made some interesting comments about Hornady claiming that the tips on their bullets were melting. This got me thinking about a news item I read years ago about the nose cone on the Concord reaching temps of 150°C (302° F) in the stagnation zone at a cruising speed of Mach 2 or 2050 fps. Looking into it further I found that the SR-71 Blackbird reached temps of around 480°C (890° F) at Mach 3.2 or close to 3300 fps. Now I have no idea at what temperature the polymer tip material the various bullet manufacturers use melts at but those temps are getting up there. Maybe one of the other more learned members can expand on this.
Kiwikid.

kiwikid said:

LDHunter in post #127 you made some interesting comments about Hornady claiming that the tips on their bullets were melting. This got me thinking about a news item I read years ago about the nose cone on the Concord reaching temps of 150°C (302° F) in the stagnation zone at a cruising speed of Mach 2 or 2050 fps. Looking into it further I found that the SR-71 Blackbird reached temps of around 480°C (890° F) at Mach 3.2 or close to 3300 fps. Now I have no idea at what temperature the polymer tip material the various bullet manufacturers use melts at but those temps are getting up there. Maybe one of the other more learned members can expand on this.
Kiwikid.

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I would also be interested in this because that speed is only reached at elevations above hunting.( does elevation affect temperature) It does trying to cook over fuel.

Hatrick the temperatures I used are the hunting elevation temperatures. At 35000 ft where the Concord flew the outside temp would be around -50 to -60° C and at the elevation the SR-71 flew it would be a few degrees colder so in actual fact the cone of the SR-71 would have been around 420° C. So if it was 0° C or 32° F the temps in my first post would be relevant for ground temps.

I can see how you could get a temperature of a airplane nose in a sustained flight situation but it's gotta be tough getting a reading on a small thing like a bullet tip. These bullet tips aren't all that tough. They almost always deform when using a kinetic bullet puller and frequently deform under recoil in a magazine box (Accubonds). Hornady's new tip may seem like a bunch of marketing hooey but I think they may be onto something. All that said, I'm sort'a liking Sierra's concept of a thick jacket and wider tip for expansion, in theory anyway. I really took note about the flame resistance of the Hornady tips. I gotta wonder why other bullet makers haven't publicly weighted in on that. Thanks to cohunt all that fascinating testing.

Mike 338 there is a formula for working out what the bullet tip temp would be but it is way above my calculating abilities. I was very interested in cohunt's test results and as soon as they are available down under in NZ I will be buying some of the 130 gr 6.5 GC for sure. I really like Sierra bullets and only really use Sierra and Norma Oryx bullets.

If i would have had some trailboss powder i could jave done a reduced velocity test also---but reload data for 7mag with trailboss shows 1400-1700 fps so I bet a 160 class bullet could be loaded to around 1200fps.

Maybe someone else with some trailboss powder could try this type of test?

cohunt said:

If i would have had some trailboss powder i could jave done a reduced velocity test also---but reload data for 7mag with trailboss shows 1400-1700 fps so I bet a 160 class bullet could be loaded to around 1200fps.

Maybe someone else with some trailboss powder could try this type of test?

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Careful downloading speed. It has the wrong effect on barrel twist. It was determined that bullets lose velocity but not so much twist. Twist was determined to aid in terminal soft tissue damage and might affect your test.

Hatrick said:

Careful downloading speed. It has the wrong effect on barrel twist. It was determined that bullets lose velocity but not so much twist. Twist was determined to aid in terminal soft tissue damage and might affect your test.

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I know, but its kind hard to test a 7 rem mag at 1200-1300 fps for minimum expansion any other way--you'd be shooting at test media out near 1800 yards--I don't know about you but I'm not a good enough shooter with a good enough gun to be shooting phone books at 1800 yards

cohunt said:

I know, but its kind hard to test a 7 rem mag at 1200-1300 fps for minimum expansion any other way--you'd be shooting at test media out near 1800 yards--I don't know about you but I'm not a good enough shooter with a good enough gun to be shooting phone books at 1800 yards

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You are exactly right. I was just throwing that out there because with your barrel you might not stabilize that bullet to hit those books at 100 yds.

Well I skipped through all these posts rather quickly but I noticed a few things. Some people have bought these bullets and tried them out, which is what I believe we all want to hear about, real data. Others haven't tried the game changers but are more than willing to get side tracked (talk about marketing, science of how a bullet works, and GUESSING what this bullet will do, not what it actually does) and show off how smart they are and judge a bullet before they try it.

So.... I'm going to share some things I've actually observed. My friend just bought a box of the 165''s for his 7mm Rem and asked me to work up a load. I checked weight, measured bearing surface, and rolled them on a flat surface to see if the tips were in line (I do this because I've seen tipped triple shock bullets where the plastic was offset to one side or completely crooked). Measured a few other things and found these bullets very consistant as far as manufacturing goes. More so than my eld-x bullets, which I've used a lot of and I still think they are a great hunting bullet. I started working up a load by finding a close to max charge of retumbo, and doing a ladder test with seating depth. In my buddies rifle, these bullets liked a .090 jump to the lands and put 3 in the same hole. The other groups from .010-.075 jump were all about 1moa.

I noticed some people talking about the tip of a bullet melting and how hornady created a great marketing hype. I watched 160 gr accubond out of a 7mm Rum start to fall out of the sky for no apperant reason at 800 yards multiple times while spotting a friend. He was frustrated that his ballistic calculator was dead nuts until 800 yards and then he would always hit low, way low. When Hornady claimed that tips were melting, that made perfect sense to me and explained my buddies problem. Obviously this was an extreme example because that little 160 gr was flying at around 3350fps. SO BEFORE GETTING SIDE TRACKED, I'll get back to the original post, I tested the game changers by adjusting the ballistic calculator until it was dead on at 300, 500, and 700 yards. Then shot out at 1000 and 1200 on the same day, with the same calculator. I did not see the bullet drop unexpectedly. Might be because it isn't moving fast enough or might be because of tip material. Whatever the explination, just some real life experience.

Hoping to shoot some game with this bullet come hunting season so I can share what this bullet ACTUALLY does and not guess at what it SHOULD do

BC, Did you have a drastic poi change with the GC bullet?
I shot both the 162eldx and 165 GC with the exact same coal and powder charge and the game changers were hitting 2.5" low and 4" left for all 8 that I shot, pretty drastic poi change , not sure why though.

I am with you though--- I weight sort my eldx because I've had as much as 1.3 grains difference from light to heavy in 1 box of them....i weighed all 100 of the gc's and they were all within .3 grains so I felt like I did not need to sort.