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Posted: 4/25/2010 10:44:33 AM EDT
[Last Edit: Molon][Edited]
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reposted; the link to the original no longer works
Observations on the Barnes TSX bullets The Barnes 70 grain TSX is a very long bullet for its weight and caliber. At a nominal length of 1.037” it is longer than the heavier 77 grain Sierra MatchKing. 
Besides being a long bullet, the 70 grain TSX has a specific gravity much lower than a copper jacketed/lead core bullet due to its sold copper construction. For example, the Hornady 75 grain BTHP has a specific gravity of approximately 10.3, while the Barnes 70 grain TSX has a specific gravity of only 8.9. The Barnes 70 grain TSX will be unstable from a 1:9” twist barrel with a gyroscopic stability factor of less than 1 at all velocities. The 70 grain TSX will only be marginally stable in a 1:8” twist barrel with a G.S.F. of 1.05 at 2500 fps. A 1:7” twist barrel will produce acceptable stability with the 70 grain TSX with a G.S.F. of 1.37 at 2500 fps. 
Barnes also makes a 62 grain TSX. It is even available in a factory load from COR-BON. Hand-loads using the 62 grain TSX consistently shoot slightly more accurately than hand-loads of the 70 grain TSX, at least in my barrels. The smallest 10-shot group from 100 yards that I’ve fired with the 70 grain TSX hand-loads had an extreme spread of 1.12”. With the 62 grain TSX hand-loads, I’ve been able to achieve sub-MOA accuracy for 10-shot groups at 100 yards. 
COR-BON 62 grain DPX 
This COR-BON load uses the Barnes 62 grain TSX bullet which has an all-copper construction. The bullet is much longer than a typical lead core/copper jacketed bullet of the same weight. This load had a muzzle velocity of 2963 fps from the 20" Colt barrel. The 10-shot group of record had an extreme spread of 1.75" and a mean radius of 0.61". 
As for the possible difference in terminal performance between the two different bullets, here is a quote from Dr. G.K. Roberts on the subject: “Keep in mind, that with non-fragmenting bullet designs, heavier bullet weights are not necessarily better, especially at closer ranges and from shorter barrels. As long as penetration and upset remain adequate, it is possible to use lighter weight non-fragmenting bullets and still have outstanding terminal performance. Heavier bullets may have an advantage at longer ranges due to better BC and less wind drift.” Can you tell the difference between the Barnes 70 grain M/LE TAC-X Tactical Bullet and the Barnes 70 grain TSX Triple-Shock X bullet? 
The picture below (courtesy of Dr. G.K. Roberts) shows the Barnes 70 grain TSX after being fired into bare gel (on the left) and after first passing through auto windshield glass and then into gel (on the right.) Dr. Roberts states that when the TSX passes through auto windshield glass "the jacket 'petals' fold back against the core, or the 'petals' are torn off; this results in a caliber size projectile configured a lot like a full wadcutter, leading to deep penetration." 
Courtesy of DocGKR 
Silver State Armory's 70 grain TSX load easily matched the reported muzzle velocity of the 5.56mm Optimized load. From a 16" Colt barrel with a NATO chamber, chrome lining and a 1:7" twist, the SSA load had a muzzle velocity of 2788 FPS with a standard deviation of 15 FPS. From a 20" Colt barrel it had a muzzle velocity of 2899 FPS with a standard deviation of 21 FPS. 
Snapshot 
As I previously posted, the Silver State Armory 70 grain TSX load had a muzzle velocity of 2899 fps from a 20" Colt barrel. This is a hot load. Factory loads using equivalent weight bullets, for example the Federal Gold Medal 69 grain Sierra MatchKing, generally run around 2750 fps from a 20” Colt barrel. Since the SSA 70 grain TSX load is such a hot load, I decided not to use my Krieger barrel, with its match chamber, to evaluate the accuracy of the SSA load. Instead, I used my 20” Noveske HBAR which has a chamber designed to fire the military pressure MK262 load safely, on full-auto, in hot environments. This barrel has a 1:7” twist. Using match grade hand-loads, this barrel turned in a 10-shot group at 100 yards that had an extreme spread of 0.726”. 
Previous accuracy testing using hand-loads of the 70 grain TSX bullet proved the bullet itself to be capable of some fine accuracy. A 10-shot group fired from my Krieger barreled AR-15 at 100 yards had an extreme spread of 1.12”. 
The SSA 70 grain TSX load was tested shooting from a bench-rest at a distance of 100 yards. A Leupold Competition scope with a magnification of 45X was used for sighting. Wind conditions were monitored using a Wind Probe. Just for kicks, I did something a little different this time. I fired two 5-shot groups! Those groups had extreme spreads of 1.22” and 1.91”. I then fired a traditional 10-shot group, which had an extreme spread of 1.93” and a mean radius of 0.61”. I over-layed the two 5-shot groups on each other using RSI Shooting Lab to form a 10-shot composite group. The 10-shot composite group had an extreme spread of 1.93” and a mean radius of 0.63”. 
As I posted previously in this thread, a barrel with a 1:9” twist theoretically will not stabilize the 70 grain TSX. Today, I put the theory to test using a Colt 16” HBAR with a 1:9” twist. This same barrel will marginally stabilize the Hornady 75 grain BTHP, though accuracy is slightly diminished compared to a 1:7” twist Colt HBAR. I fired a 10-shot group of the 70 grain TSX round at a distance of 100 yards using the 1:9” twist barrel. Accuracy was terrible; the group had an extreme spread of over 3 inches. Several of the bullet holes were slightly oblong in shape and a coulple of the bullet holes were clearly “key-holed” demonstrating that a 1:9” twist barrel will indeed not stabilize the 70 grain TSX. 
The TSX as a Barrier Load When the TSX is shot through autoglass, the "petals" tend to shear off, or collapse in on themselves.
Courtesy of Dr. Roberts |
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| Great post and thanks for the info, I have been considering getting the Barnes 62 and 70 solid copper bullets for hog hunting and now I am going to order some to try out for said purpose. I really like the length of them and should work well as all my 5.56's are 1:7" twist too. |
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Originally Posted By marinesg1012:
Do you by chance know the min opening velocity for the 70 TSX? is it 2100 FPS or so? The TSX's are great bullets but velocity is the key for them... I didnt know a 62 grain TSX was available... is the corbon ammo loaded to 556? If memory serves it is 1800 fps. P |
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Originally Posted By marinesg1012:
Do you by chance know the min opening velocity for the 70 TSX? is it 2100 FPS or so? The TSX's are great bullets but velocity is the key for them... I didnt know a 62 grain TSX was available... is the corbon ammo loaded to 556? http://www.cor-bon.com/ http://www.barnesbullets.com/products/loaded-ammunition/ |
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Originally Posted By marinesg1012:
I didnt know a 62 grain TSX was available... is the corbon ammo loaded to 556? Negative. |
All that is necessary for Trolls to flourish, is for good men to do nothing.
In God We Trust. Everyone else needs to post data.
In God We Trust. Everyone else needs to post data.
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Originally Posted By DocGKR:
We actually are liking the 55 gr TSX (commercial loads available from Black Hills and Federal)... Hmmm . . . |
All that is necessary for Trolls to flourish, is for good men to do nothing.
In God We Trust. Everyone else needs to post data.
In God We Trust. Everyone else needs to post data.
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Originally Posted By Molon:
Originally Posted By DocGKR:
We actually are liking the 55 gr TSX (commercial loads available from Black Hills and Federal)... Hmmm . . . Indeed. I load the 62gr TSX as a pig slayer, and it does a fantastic job. Wouldn't be much difference in the 55gr TSX (a little boost in velocity perhaps)... |
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Originally Posted By Hector45:
Now I can't decide, I'm trying to make a boar/deer round, should i go with the 62gr TSX or the 70gr TSX. The length of the 70gr scares me a little. I'm telling you right now, you do not need the 70gr. The 62 will do anything the 70 will do, only shoot a bit faster 
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Originally Posted By QuicksilverJPR:
Originally Posted By Hector45:
Now I can't decide, I'm trying to make a boar/deer round, should i go with the 62gr TSX or the 70gr TSX. The length of the 70gr scares me a little. I'm telling you right now, you do not need the 70gr. The 62 will do anything the 70 will do, only shoot a bit faster What type of powder are you using in your 62gr load? |
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Originally Posted By Molon:
Originally Posted By DocGKR:
We actually are liking the 55 gr TSX (commercial loads available from Black Hills and Federal)... Hmmm . . . doulbe 'Hmmm...'. I wonder if it's short enough to stabilize out of a 1:12? Dr Roberts you wouldn't happend to have measured the length of a 55gr TSX bullet by any chance? |
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6.8 > 6.5
6.8 > 6.5
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Originally Posted By Hector45:
Originally Posted By QuicksilverJPR:
Originally Posted By Hector45:
Now I can't decide, I'm trying to make a boar/deer round, should i go with the 62gr TSX or the 70gr TSX. The length of the 70gr scares me a little. I'm telling you right now, you do not need the 70gr. The 62 will do anything the 70 will do, only shoot a bit faster What type of powder are you using in your 62gr load? Ramshot TAC and AA-2520. Offhand, the TAC load maxes out at 24.5 grains, IIRC... |
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Molon,
I came across your posts while researching a good load for home/self defense. I currently employ orange box 75 grain TAP but I wanted to make sure that was still the way to go before ordering more. Would you mind telling me after all of your research, what you personally use as your "go to" round? |
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Originally Posted By Swat_dude:
Molon, I came across your posts while researching a good load for home/self defense. I currently employ orange box 75 grain TAP but I wanted to make sure that was still the way to go before ordering more. Would you mind telling me after all of your research, what you personally use as your "go to" round? At this point in time my personal defense load is still the Hornady 5.56mm TAP T2 load. I also keep different colored magazines loaded with the Speer 64 grain Gold Dot close at hand. (Specifications subject to change without notice. )
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All that is necessary for Trolls to flourish, is for good men to do nothing.
In God We Trust. Everyone else needs to post data.
In God We Trust. Everyone else needs to post data.
|
Originally Posted By Swat_dude:
Molon, I came across your posts while researching a good load for home/self defense. I currently employ orange box 75 grain TAP but I wanted to make sure that was still the way to go before ordering more. Would you mind telling me after all of your research, what you personally use as your "go to" round? There is a new kid on the block, try some of this: 2930 fps and 1,430 ft lbs out of a 20" barrel with a 75 grain pill http://www.cheaperthandirt.com/70724-1.html |
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Originally Posted By Hatr40:
Way to dig up a 7 year old thread. Were you just going to bitch about not supporting the site??? People like you are the reason molon left I was excited, I thought molon was back |
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Originally Posted By EzGoingKev:
I read recently Barnes copper projectiles copper foul at a higher rate than a standard jacketed round. Has anyone found this to be true? Originally Posted By EzGoingKev:
I read recently Barnes copper projectiles copper foul at a higher rate than a standard jacketed round. Has anyone found this to be true? Originally Posted By Hatr40:
Way to dig up a 7 year old thread. |
"with a Big Iron on his hip" - Marty Robbins
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Originally Posted By leid:
Only for the past decade or so on the large 250lb. whitetail I hunt during the rut. Photobucket has my hunting pics locked up for ransom or I would post the actual terminal performance pics I have posted here on arf.com over the past decade. I shoot paper only in preparation for shooting flesh & bone targets. |
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Originally Posted By leid:
Only for the past decade or so on the large 250lb. whitetail I hunt during the rut. Photobucket has my hunting pics locked up for ransom or I would post the actual terminal performance pics I have posted here on arf.com over the past decade. I shoot paper only in preparation for shooting flesh & bone targets. Originally Posted By leid:
Originally Posted By Jormungandr:
Have been thinking about 70gr tsx for some white tail hunting this year. Anyone use em before? |
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Originally Posted By leid:
Only for the past decade or so on the large 250lb. whitetail I hunt during the rut. Photobucket has my hunting pics locked up for ransom or I would post the actual terminal performance pics I have posted here on arf.com over the past decade. I shoot paper only in preparation for shooting flesh & bone targets. |
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Originally Posted By EzGoingKev:
Who cares how old it is? I did a search, found this thread, and posted in it. I would rather resurrect this thread and have all the info in one place instead of spread across 25 threads. Originally Posted By EzGoingKev:
Originally Posted By Hatr40:
Way to dig up a 7 year old thread. Still trying to get a steel/autoglass test with the 62gr TSX |
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Originally Posted By TaylorWSO:
you know this site is about AR knowledge and is a repository for it, right??? Were you just going to bitch about not supporting the site??? People like you are the reason molon left I was excited, I thought molon was back Leid... don't let the petty members win. The petty bickering is tiresome. Quit taking other peoples internet comments to heart. Take from the site info, but please leave out the unwanted and unnecessary crappy comments.... at the very least try to post comments in a less snotty tone. Consider where we would all be without forums like this. For the current question posted.... Barnes "used" to have an issue with the copper alloy used in their bullets, they have steadily been working to minimize that problem. Different alloys, the bands on the bullets all help a lot in cutting back copper fouling. From the Barnes webpage... Can I expect copper fouling when using TSX Bullets? Because of mutiple grooves machined into the shanks of TSX bullets, less bullet area comes in contact with the bore. This reduces pressures and virtually eliminates copper fouling. Is it true TSX Bullets will wear out my barrel more quickly than jacketed bullets will? As long as you clean your barrel frequently, there is no way TSX bullets will wear out your barrel any faster than other bullets. We have fired thousands of TSX Bullets through our barrels without seeing any unusual wear. |
*Hold on to your AR-15s. Their magic must be very powerful, or they wouldn’t want them.*
JAFOM.... Just another fat old man.
JAFOM.... Just another fat old man.
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A few invaluable members like Molon, spend their time and money expertly evaluating ammo, guns, barrels etc, and then collating the data and articulately posting it for all to enjoy and hopefully learn.
And invariably, it turns into a shit storm of ignorant and contradictory opinions and bashing of the data. I wish everyone could just absorb the knowledge and say "thank you". |
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My DD with a 16" barrel 1/7 twist loves the 70gr TSX bullets. I can easily shoot 1/2 MOA all day long at 100 yards with it. I haven't shot a deer with it yet but from what I've read, the TSX bullets are excellent. Fleet farm had the 140gr 7mm TSX bullets on clearance for 13 bucks (qty 50) last year. I bought everyone they had. I have some loaded up for my Steyr in 7mm-08 but haven't tried them yet. |
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