Savage 6mm creedmoor and Hornady 108 grain match ammo - issues and analysis; blown primers

[Robinhood]

In that picture it looks like your bolt face is pitted. I see 2 cases with primers missing. Maybe a few more that have gas burns around the primer. Unacceptable. I think Hornady has a problem. Stop using that ammo.

[mnbogboy2]

How many rounds through it. To me it appears it has a "tight" throat or throat with burrs (these usually are gone after a few rounds). Another possibility is the chamber misaligned with the bore. If it is misaligned the sharpie mark on the bullet will always be clocked at the same position (not even all the way around). If the ammo is way out of concentricity it may mark to one side also but not consistent clocking.
It may be worth a couple of more checks.
Thinking outloud.

[steve101610]

Can you take some better pics of the fired cases from the 108eldm rounds. It’s hard to tell from the pic but it looks to me like there is some ejector marks on the brass. From looking at the marker test pics it looks to me like the 108s are getting jammed into the lands. This is actually a pretty common issue with the 6mm creedmoor because of different throat lengths on different reamers. My criterion 6mm creedmoor barrel was cut with a pre saami reamer and has a really short freebore.


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[celltech]

For my own curiosity...measure the 108 post test...did it jam hard enough to push the bullet in?

[miscverb]

You can seat the bullet a little deeper for the savage as it sounds like it has a shorter throat than the ruger or browning and is engaging the lands before it is ever fired and that will produce a pressure spike and likely is causing your blown primer issue.

i don't have the gear for that.... yet

[miscverb]

Can you take some better pics of the fired cases from the 108eldm rounds. It’s hard to tell from the pic but it looks to me like there is some ejector marks on the brass. From looking at the marker test pics it looks to me like the 108s are getting jammed into the lands. This is actually a pretty common issue with the 6mm creedmoor because of different throat lengths on different reamers. My criterion 6mm creedmoor barrel was cut with a pre saami reamer and has a really short freebore.


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regarding jammed into the lands, i did a test whereby i pushed both the 105g and the 108 grain into the chamber/barrel with my finger, tightly/hard. neither bullet got "stuck" and both bullets fell out freely. the "test" to see if the bullet was jammed in the lands did not seem to come back positive; meaning it wasn't jammed in the lands. that was a simple test i found on youtube so i don't know how viable it is, but it makes common sense.

all of this is very insightful and will help one day when i do begin reloading.

[sharpshooter]

Like I said all along...it's the ammo! Have you guys overlooked the fact that all Savage rifles are proof tested and function fired? If a 68,000 psi proof load blew a primer, it wouldn't get any farther than that.

[miscverb]

Like I said all along...it's the ammo! Have you guys overlooked the fact that all Savage rifles are proof tested and function fired? If a 68,000 psi proof load blew a primer, it wouldn't get any farther than that.

to update everyone that is interested, i did a good amount of testing yesterday. the summary of the testing is:

HISTORY
- the suspected bad ammo lot number ends in 270. It is Hornady 6mm Match 108g eld.
- I had experienced blown primers previously with this lot and with the savage.
- i MAY have had other blown primers with lot 270 the other rifles but i did not record that as a known event (wasn't sure)
- the rifle that was used and known that had blown primers was the savage 6mm, with lot 270
- the savage 6mm has no other sings of a tight chamber, bolt easy to close, no marks on bullets from lands, no issues with other ammo, etc
- the savage has never had any issues with any other 6mm ammo, only the 108 grain eld match. I have shot Hornady 105grain bthp with no issues at all, in all rifles.

TESTING

for testing i also used a ruger rpr 6mm and a browning eclipse target 6mm for testing

i started with the savage and tested another lot of ammo we will call ABC, no issues
i tested lot ABC with the browning, no issues

i went to lot DEF tested the savage, ruger, and browning, no issues
i went to lot GHI tested the savage, ruger, and browning, no issues
i went to lot JKL tested the savage, ruger, and browning, no issues

then i went to the known 270 issue lot, new box of ammo, and started to test with the savage. i wanted to start testing with the savage since if it will blow primers i did not want to damage the ruger or browning gun bolt

shot 1 round from lot 270 with the savage, ok
shot 2nd round from lot 270 with the savage, BLOWN PRIMER
STOPPED TEST of lot 270

ALL issues seem to be with lot 270. i will be sending Hornady 3 boxes of the 270 lot ammo for analysis, which I have about 20 boxes of... uggg.... When I do/did get the blown primers it was 2 to 3 rounds per box.

I then shot the Hornady 105 grain BTHP out of all three rifles and no issues. all issue indications lead back to lot 270

QUESTION: When ammunition manufactures produce a lot of ammunition, how many rounds are in a "lot"? just curious.

[celltech]

Even with the "good" ammo lots are you getting other signs, like the cratered primers? Are the good lots any shorter in overall length? And I don't suppose you have a scale and could weigh out the powder charges between the 2 lots....

[miscverb]

Even with the "good" ammo lots are you getting other signs, like the cratered primers? Are the good lots any shorter in overall length? And I don't suppose you have a scale and could weigh out the powder charges between the 2 lots....

i will check those items and record results. i don't have the tools/scale to measure powder charges, BUT i have friends that do. Great idea! STAY TUNED...

[jpdown]

Based on my Savage 6mm Creedmoor Desert Tactical chamber measurements, the bullet is firmly touching the lands with Hornady 105 gr BTHP at an overall cartridge length of 2.756". I suspect if you measure your rifle using the right tools, you'll find the Hornady factory 108 gr ELD's with an overall cartridge length of 2.79" (within SAMMI specs.) are jamming the 108 gr bullets into the lands causing over-pressure and blown primers.

[Robinhood]

Done correctly by process of elimination. This does not mean that you are not close to or touching the lands causing high pressure with the 108's. You will need to either push the bullet in at least .030, have it throated or roll your own with a shorter COAL/BTO.

Something you may want to look at around the primers. https://proxy.duckduckgo.com/iu/?u=https%3A%2F%2Fsites.google.com%2Fsite%2Fhobbyhi ntstricksideas%2FHome%2Fs-w-329pd-info%2Fzoom_primer_split.JPG%3Fattredirects%3D0&f=1

That can cause something similar to this
https://proxy.duckduckgo.com/iu/?u=https%3A%2F%2Ftse1.mm.bing.net%2Fth%3Fid%3DOIP. w4g8SXx8VFyWXsjrkH3eCgHaFH%26pid%3D15.1&f=1

https://uc3cc7808ae07ea7738ca93f5b1d.previews.dropboxuserc ontent.com/p/thumb/AAQdRZxDxlRVwCdvQ0CiBMoD6NjN3j47qVLQVTxhycTNpSx4Bx wPiYaKS7z4eX9MgmPoY-MpzknjozsazIVjlfrdiqzeoaKgVDCmDYN7-RWAG9cUvh_KUEwmuqU7YLX4-4TrB7rZJW_j5kgdJbTRtMl14S8S9IWVrsrHgx6MATnVx7SuETf D2bmNJFqqg3GZUDoH53EKtvpK2lW4tqmYNZQBUX-OH2JearKiPdfwVZzAgoOCIPWOSgDjiRK1_0FiMJ-5SQda0XQgyZJ_o5BN5II2/p.jpeg?size_mode=5

If the primer is pierced around the firing pin dent then the hot gasses will cut around your firing pin hole. This can create issues down the road.

If you bolt head is damage get with member Grimstod Desh. Great reputation for repairing bolt heads...or get a new one.

[miscverb]

Based on my Savage 6mm Creedmoor Desert Tactical chamber measurements, the bullet is firmly touching the lands with Hornady 105 gr BTHP at an overall cartridge length of 2.756". I suspect if you measure your rifle using the right tools, you'll find the Hornady factory 108 gr ELD's with an overall cartridge length of 2.79" (within SAMMI specs.) are jamming the 108 gr bullets into the lands causing over-pressure and blown primers.


my testing is in line with your information, and has shown that the 108s with a length of 2.79xx would blow in the savage and would not blow in the ruger. my testing also showed that anything less than 2.79xx would not blow in the savage. of the 270 lot of ammo, they are a bit longer on average in the 2.79xx ranger than the other lots i have measured. as someone else noted, it probably makes sense to get the savage throat extended a bit.

[steve101610]

I wouldn’t get the throat extended. The 6mm Creedmoor is really hard on throats and will erode very quickly.


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[miscverb]

I wouldn’t get the throat extended. The 6mm Creedmoor is really hard on throats and will erode very quickly.


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hummm.... ok... i may just use the "bad for the savage 270 lot" in the ruger then, did not bother the ruger rpr, and shoot other "good lots" in the savage... problem solved! i hope. the savage has about 510 rounds through it now. thanks for the feedback