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Berger tests regular vs. thick jackets with Bartlein - Unexpected Results

On January 3rd of 2007 with the help of Mid Tompkins we were able to test our new,at that time) thicker jackets to see if they did in fact eliminate bullets failures. Two Krieger barrels were provided and the test was a success. We produced 62 failures out of 510 shots using the regular J4 jackets. When we switched to the thicker jacket bullets no failures occurred in 440 shots.

The results of this test lead to our separating our entire line into 3 application based lines. The Target line is made using only thick jackets while the Hunting and Varmint lines are made using the standard jackets. Since then the occurrences of bullet failures is nearly zero.

After the results of the 2007 test we were approached by Bartlein and Broughton. These manufacturers offered barrels for additional testing. I am not interested in testing barrels as I believe there are too many variables and too few tests to provide a truly scientific result. I did want to prove that our theory was based on repeatable results so I agreed to further testing.

It took two years but on February 3rd we were at Ben Avery Shooting Facility with two Bartlein barrels and specific expectations. Attached are the results from this test.

As you will see the test was not completed. We shot 450 shots,regular jackets) in a little over 3 hours and even though we had 48 blown primers and a chronographed MV averaging 3,150+ we could not get one bullet to fail. We started shooting the thick jacket bullets but 11 of the first 15 rounds had blown primers. We did not want to ruin Mid and Nancy's gear or injure anyone so the decision was made to stop the test.

Mid switched out these barrel with some of their match barrel and within 15 shots both extractors broke in both actions. I truly appreciate Mid not only taking the time to chamber these barrels and load all the ammo but he sacrificed his gear in the interest of improved performance for rifle shooters. I can't say enough good things about him and many know how much he has given of himself for the benefit of others.

I promised Bartlein that I would publish the results. Take from this information what you can. We are considering extending the test using the Bartlein barrels to a greater number of shots. Remember the point of this test is to create bullet failures with regular jacket bullets and then shoot thick jacket bullets to see if the failures stop. Our significant abuse of the Bartlein barrels failed to produce bullet failures so we are going back to the drawing board.

Regards,
Eric
 

Attachments

Eric,
I apologize if I missed this but was this a 5r or what was the groove configuration of the barrel?


James
 
Hi Eric...good to see that you are relentless at cureing the jacket mystery....
Please tell us what kind of action were in use and what type of extractor ...were the primers blanked to the point that the fire control required removal and cleaning...and the fireing pin diamater ....there is lots to be gleaned from your efforts...Thank YOU...Roger
Sorry for my blaterings...and confusion...We realize the cal. was 6.5x 284...this was a test of the action not the bullet...the action,both of em) was put to the test,I was wondering which brand or type stood all this abuse,,and the trigger))...if they want to do a velocity/bullet test they shulda chamberd somenting with a lot more steam like a 6.5-06 or,gasp, a WWH or its equal...then they wuld have had the velocity at their disposal and culd have tried em at 3100--3200--3300 and rellly seen wht they were capable of ...lots of hunters shoot the bigger cases and the puny lil 284 didnt proove much to us....hope this clarifies my line of questioning,I apologize for the confusion....Roger
 
Eric,

Thanks for the report. People need to understand that these tests were with the 6.5-284 cartridge, using H4350 powder.

The velocities at which testing was done, 3100+ fps, is WAY faster than most 6.5-284 shooters drive their bullets. So, in my mind, the blown primers etc. is not an indicator of some problem with the barrels. What it shows is that the pressures were WAY over "practical max." This was done, doubtless, to expose the bullets to the highest level of heat/pressure possible.

It might be interesting to try the tests again with Reloder 17, if the purpose is to achieve max velocities, but stop short of gear-busting pressure levels.
 
James,

This barrel was a 4 groove standard configuration. Bartlein barrels are cut rifling.

Hello again Roger,

Below is a copy of my response to your post from BRCentral.com

This brings me to your questions. The actions were Stolles. They belong to Mid Tompkins and Nancy Gallagher so I am not very familiar with the particulars. I believe they use the standard Stolle extractor. I know one trigger was an Anschutz while the other was new,and not an Anschutz) but the maker escaped me.

The blown primers fell out of the cases. A flick of a finger removed the primer from inside the action and shooting continued. No cleaning or measuring was done while we were shooting. We did measure the diameter of the case head and found it to be .009 larger than an unfired case which is why,we believe) the primers were falling out.

In this test the 6.5X284 was chosen since many reports of failures came from F-Class shooters using this case. Since this was the source of the concern it seemed the best place to start. Remember that bullet failures occur during strings of firing many bullets. To date not one report of a bullet failure has come from a hunter.

Paul makes a great point.

To be clear, I am not suggesting that anything at all was wrong with the barrel. In fact, the results from this test indicate that Bartleins are less likely to create failures since the conditions were harder on these barrels/bullets than in the previous test.

The increased velocity was the result of using a different lot of powder. We used the same load,weight of the charge) of H4350 as we did in the previous test. This lot of H4350 was much hotter than the previous lot.

This is a clear example as to why loads should be checked each time the powder lot changes. This is also the reason why no two loading manuals will have the same data.

Powder's burn rate varies considerably from lot to lot and all reloaders need to internalize this truth. The consequences of not understanding this truth can result in anything from poor precision to personal injury or even death.

I believe that if the load was adjusted to produce the same 3,000 fps MV as the first test the number of failures and blown primers would have been zero.

Regards,
Eric
 
An important fact about the barrels has been brought to my attention by Bartlein. Both barrels had a bore diameter of .256 however the barrel with a .265 groove diameter was a 5R rifling configuration. The barrel with the .264 groove diameter was a standard 4 groove.

Regards,
Eric
 

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