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Discussion Starter · #561 · (Edited)
I'm still testing bullets but not at the rate I used to. I've had to make room in my workshop for a new project restoring a 1960 MGA which I've owned since 1980. I've reorganized my brass and bullets to save space, but decided it was time to dispose of all the recovered bullets. I've done well north of 500 tests. The bullets were all sorted in zip-lock bags by test. The copper bullets made it into the recycle bin. Here's a pic of just the Barnes and Hornady GMXs that were tested before they were sent "down-range" on their final journey.

Thanks to all those that have contributed bullets for testing.

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I'm still testing bullets but not at the rate I used to. I've had to make room in my workshop for a new project restoring a 1960 MGA which I've owned since 1980. I've reorganized my brass and bullets to save space, but decided it was time to dispose of all the recovered bullets. I've done well north of 500 tests. The bullets were all sorted in zip-lock bags by test. The copper bullets made it into the recycle bin. Here's a pic of the Barnes and Hornady GMXs that were tested before they were sent "down-range" on their final journey.

Thanks to all those that have contributed bullets for testing.

View attachment 76119


This does not signal the end of this thread.
Thats a great collection of bullets. I have a nice box full of bullets I've tested but I've only done around 50 tests. I always just did them for the hell of it, until one day my dad told me I should try to share my results with people. That's when I decided to start making YouTube videos and sharing my results on here. I'm definitely not a great video editor or creator but I enjoy sharing my tests. I've done so many ballistics gel tests that I never made videos on because I was too lazy to set up cameras and edit videos. I didn't label most the bullets I've captured so at this point I barely remember what is what
 

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I'm still testing bullets but not at the rate I used to. I've had to make room in my workshop for a new project restoring a 1960 MGA which I've owned since 1980. I've reorganized my brass and bullets to save space, but decided it was time to dispose of all the recovered bullets. I've done well north of 500 tests. The bullets were all sorted in zip-lock bags by test. The copper bullets made it into the recycle bin. Here's a pic of just the Barnes and Hornady GMXs that were tested before they were sent "down-range" on their final journey.

Thanks to all those that have contributed bullets for testing.

View attachment 76119


This does not signal the end of this thread.
The weight retention of the copper Bullets at least the Barnes is unmatched by any lead bullet by far.
120 gr 6.5cm still 119 gr into the 4 jug of water >2900 fps @ muzzle.
 

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Discussion Starter · #564 ·
115gr XP from Winchester

While driving through Colorado last week, I stopped in a Scheel’s, a retail sporting goods store. They had a shelf full of 6.8 ammo, more than I’ve ever seen in one location. Their selection included the new 115 XP from Winchester that many on the forum have inquired about. It has been a while since doing a 6.8mm terminal performance test, so I plunked down $35 ($5 cheaper than Midway) and brought a box home to test.

The XP is a non-bonded, lead-core bullet with a larger than normal plastic ballistic tip – a unique feature as you can see in the side-by-side comparison with the 110 PTS from S&B and the 120 MKZ from CavityBack, all factory ammo. The XP’s tip was easy to pull exposing a lead core with no expansion cavity. The copper jacket was 0.015” thick at the tip. In the cut-away comparison with the SST, there are no internal locking rings in the flat-based XP’s copper jacket. Contrary to Winchester’s #1 marketing statement, the addition of a ballistic tip does not facilitate bullet expansion. I’ve tested numerous tipped bullets and their expansion was greater with the tips removed (see link below). Also, adding a ballistic tip to a bullet designed without a tip typically retards expansion. Muzzle velocities were less than the advertised 2625 fps. BC was measured with a LabRadar.

6.8 SPC Bullet Performance

From 6.8 SPC II - ARP 1:11 barrels (75F)
115gr XP muzzle velocities (fps)
2470 from 12.5”
2555 from 16”
2625 Advertised
[BC (G1) 0.317 measured, 0.135 without the tip]

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Discussion Starter · #565 ·
Observed Terminal Performance: 115gr Winchester XP

Terminal performance testing was accomplished with the standard set-up comprised of a gallon water jug in front of a bullet trap containing a 1500-page phonebook backed up by 15 magazines and bulk paper. As expected, the XP is a fragmentation bullet similar to the SST. The water jug’s reaction to the impact was mild. Recovered bullets were mushroomed with weights ranging from 55 to 65 grains. Penetrations were through the phone book and a couple of magazines which has proven effective on deer. The lead cores remaining in the copper jackets were loose and fell out when removed from the bullet trap. Similar to the SST, hunters may find the copper jacket separated on the off-side deer’s hide due to the loose core. Some ballistic tips were found whole. Lead fragmentation was occurring almost immediately after impact as can be seen in the right-side picture insert. This specific test required a re-do because the bullet hit the top, handle-side of the jug which is angled at 45 degrees and has less water depth causing the bullet to yaw. However, the impact clearly showed multiple fragments going through the foam-core panel backing the jug. Lead fragments were also found with the other bullets but were not as easily seen in a photograph.

This off-center impact is a segue to the issue I had with this bullet; 3-shot groups were 1.75 to 3 MOA at 100 yards in rifles that are otherwise accurate. Groups seemed to get worse at 200 yards which made hitting a gallon jug problematic. No testing was performed at a further distance. If anyone else has shot this bullet, please share your experience with accuracy.

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Note: Go to the First Page for Quick Links to other bullets tested
 

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I have shot it from several .243. Some are accurate and some don't like it at all. Performance on deer seem to be terminal, although far hide often stops exit. Blood trail is minimal or non existent.

If in thick cover, I would recommend not using, but if wide open and easy to see where it will drop dead, they are fine.
 

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Discussion Starter · #570 ·
From what I understand, Speer made the 6.8mm Gold Dots specifically for Federal Ammunition. A few years ago, Speer began selling them as a component. Today, a search of Speer.com and Ammoseek.com shows them to be unavailable. Beware that Speer exaggerates their BCs by as much as 30%. I tested the 115 GD multiple times, and their measured BC was 0.301.
 

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@Xman Thanks. I bought some a couple of years ago. I think I'm going to try them in 6.8 for deer and hogs. Your results make the Gold Dot look impressive. Oldest grandson got a nice whitetail buck year before last with a Sierra 110gr PH. Neck shot at about 140yds, DRT. We've gotten 1 or 2 doe since with the 110SPH. Going to get set for pigs at night this coming season.
 

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Discussion Starter · #573 ·
Olyellar, I grabbed some 100-grain CX components when they were available last month. The 100 GMX it replaces was an excellent copper bullet, expanding well and holding together even in-close. Below is a side-by-side comparison: 100g GMX on the left and CX on the right. The external profile measured the same for both versions. The CX has the new heat/friction-resistant tip material that Hornady is using. They have also changed the metallurgy of the new CX for improved expansion but will not divulge what the new composition is. Note that there is only a single instead of two pressure-relieving grooves. The grooves on the CX bullets are now a radius indentation which improves BC compared to a square cut. If you look closely at the image, there is a slight impression in the CX's bullet shank where the second groove used to be, like it was removed from a mold. Note, I communicated with Dave Emary back when the GMX was introduced, and he advised that more than two grooves (like Barnes bullets) did not provide significant additional pressure relieve. Interesting that Hornady made the effort to remove the second groove.

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Discussion Starter · #574 · (Edited)
I have completed an initial check of the CX for BC and terminal performance using a 14” ARP barrel. With an average muzzle velocity of 2706, the CX measured BC (G1) was 0.303, significantly more than the advertised BC of 0.262. This is a slight improvement over the 100 GMX that measured 0.297 during this range session, consistent with the BC measured in 2017.

More important, is the CX's terminal performance. The range was busy with activity, so a minimum velocity test could not be conducted. Both the GMX and CX had an impact velocity of 2510 fps at 60 yards into a gallon water jug and bullet trap, measured with a LabRadar. This test indicates that the CX will expand as much or more than its predecessor. Both the GMX and CX expanded to 0.5” with an insignificant difference. However, you can see from the picture that the CX expanded further into its expansion cavity shortening from its overall length of 1.125" to 0.455" compared to 0.500" for the GMX. This points to improved expansion at lower velocities.

Low-speed test is in post #579 below

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Discussion Starter · #575 · (Edited)
Side notes. Hornady has been contacted to suggest they double-check the BC data for the 100 CX but has not responded. Hornady also lists their 6.8 CX ammo with a muzzle velocity of 2550 fps with a 24” barrel. I would hope this is in error, also. A mv of 2550 fps from a 16" barrel is not pushing the pressure limits. I was getting 2700 fps from a 14" barrel with a mild handload. The ballistic table they list on their website may even have errors in their down-range velocity for a 0.262 BC. It is likely that some employee was rushed inputting the data to meet a press deadline. Hornady sure didn’t do the 6.8mm SPC any favors with their release of under-performing data. I wouldn't let their publishing errors stop you from trying a box or two. If someone does buy some factory CX ammo, please share your velocity results.

Hornady lists muzzle velocity of their factory ammo at 2550 fps
zimagold reported a 10-shot average 0f 2608 fps from a 16" ARP and confirmed a BC of 0.3 (G1).
 

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Jumping back to the Winchester XP....also I believe labelled Deer Season XP in other calibers. From what I have researched and read on these bullets the design was intended to pass through and disintegrate to do maximal damage in the chest cavity. The thinking seems to have been to do enough damage right there to drop a deer. Not sure I can buy into that theory and not sure the bullet would hold together enough to exit in the lighter weights. From an accuracy perspective that big tip could certainly be adverse if not perfectly centered.
 

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Discussion Starter · #579 · (Edited)
Minimum Velocity 100 GMX vs new 100 CX Testing (High-speed Test in post #574 above)

The results of this test were unexpected. Even though the CX expanded slightly better than the GMX at high-speed, the 100 CX failed to expand at 2000 fps and yawed. The 100 GMX, which has Hornady's 2nd generation expansion chamber, reliably opens below 1700 fps. You can see how wide and well developed the GMX's expansion cavity became in this low-speed test (lower center insert). The GMX's pedals do breakoff going through the phonebook so used just wet newspaper in past tests to measure full expansion (prior GMX test shown top center). Only the water jug/phonebook bullet trap was available for yesterday's test.

Monolithic bullets have reliably expanded when impacting water jugs. It will likely be after hunting season before I can confirm the 100 CX's minimum opening velocity.

Update: 4 October, conducted four additional CX terminal performance tests with impact velocities from 1900 to 2200 fps with all tests resulting in bullet yaw with no expansion. This will take a while to figure out what is happening.

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Minimum Velocity 100 GMX vs new 100 CX Testing (High-speed Test in post #547 above)

The results of this test were unexpected. Even though the CX expanded slightly better than the GMX at high-speed, the 100 CX failed to expand at 2000 fps and yawed. The 100 GMX, which has Hornady's 2nd generation expansion chamber, reliably opens below 1700 fps. You can see how wide and well developed the GMX's expansion cavity became in this low-speed test (lower center insert). The GMX's pedals do breakoff going through the phonebook so used just wet newspaper in past tests to measure full expansion (prior GMX test shown top center). Only the water jug/phonebook bullet trap was available for yesterday's test.

Monolithic bullets have reliably expanded when impacting water jugs. It will likely be after hunting season before I can confirm the 100 CX's minimum opening velocity.

View attachment 77603
Original high velocity comparison is in post 574 not 547
 
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