over pressures 6.5 grendel

[misser]

always been told to look for pressure signs when working up my own loading's ya thats ok, i understand that .i picked up a box of hornady black 123 sst to try . first thing was the brass being kicked out to 2 o'clock .my own loadings to 4 o clock . retrieve the brass from the box 6.5 to find flat primers very flat primers. whats up with that ?

 

[Jager]

I wouldn't assume over pressure based simply on what you've described. The factories have rigorous measures in place to ensure their ammunition adheres to SAAMI spec. There's too much liability to not do so. And "flat" primers are probably the most unreliable pressure sign in the handloader's toolkit. Nor is the spot where a semi-auto ejects its brass much of an indicator of anything.

Chrono data would give you more insight.

 

[Mark611]

IMO, another thing that could cause that, is if you had any cleaning solvents left over in your chamber or bore, I had this happen myself, also I have noticed that some powders in the 6.5 Grendel when you get up close to max charge weights show pressure signs in the primers and ejector marks, this is from an AR plat form, I don't know what powder your loading? but I have had issues SWMR, A2460, the best powder I have found so far for the 6.5GRR is AR Comp, out of about 9 different powders I have tried for this cartridge, this is out of 18'' and 24'' tubes, with 120 and 123gn pills, YMMV

 

[Turpentine]

IMO, another thing that could cause that, is if you had any cleaning solvents left over in your chamber or bore, I had this happen myself, also I have noticed that some powders in the 6.5 Grendel when you get up close to max charge weights show pressure signs in the primers and ejector marks, this is from an AR plat form, I don't know what powder your loading? but I have had issues SWMR, A2460, the best powder I have found so far for the 6.5GRR is AR Comp, out of about 9 different powders I have tried for this cartridge, this is out of 18'' and 24'' tubes, with 120 and 123gn pills, YMMV

From what I've seen with the Grendel if your rifle doesn't like AR Comp you likely have a rifle problem. About every Grendel I have ever shot liked 27.7 grains ARComp with a standard primer and 123 eldm. Truthfully anywhere from 27.5 - 27.9 does well with Fed 205 ar primers but I get lower ES sand Sd at 27.7. We get some very hot days so I tend to prefer the more temp stable stick powders to ball.

With Privi Partizan 120 hollow points I have had blown and pierced primers when temps were over 90 degrees. I buy these sometimes just for plinking and the brass.

OP what was the temp when you were shooting?

 

[Mark611]

I also use CCI#41's and Winchester standard small rifle primers with good results!

 

[Turpentine]

I also use CCI#41's and Winchester standard small rifle primers with good results!

In two of my rifles my groups were pretty good with CCI 41s but my ES and SD numbers were much higher. Really no big deal as I can just use the 41s in my 223 for now and they like the 41s.
I recently had some ExaKt small rifle primers sent to me in a dealer botched order. To fix the issue he just sold me those at cost and then sent the large rifle primers that I asked for. I'm really kind of anxious to see how they do as there's very little info out there on them.

 

[Mark611]

I don't push my charge weigh as hi as you do, I run 27.1gns with the WSRP's and CCI#41's, out of my 18'' 1&8 and get 2495fps with SD's of 7, my 24'' 1&8 same load I get 2545fps with SD's of 7, with 120gn SMK's, accuracy 3/4 in groups @200m, I'm pretty happy with this, I struggled with this cartridge with accuracy and velocity until I started using AR Comp, I see no reason to use another powder,

 

[Turpentine]

I also struggled with mine. My first barrel, A 20" 1 in 8 twist was very finicky. My 20" AA 1 in 9 was very easy to find a load for. i could likely do a new workup with the 41s that would work fine but the 223s like them so I'm happy where I am. With the 27.7 load I'm at or just below 2500 in both with 123 eldm. H4895 was also very accurate and my 1 in 8 loves Power Pro Varmint. I just don't care for ball powder.

 

[Mark611]

I have also tried H4895, H322, TAC, A2460, A2495, A2520, Shooters World Match Rifle, and a few more, nothing come close in my rifles as far as accuracy and performance like AR Comp.

 

[mattri]

Putting a Grendel together on a bolt platform will be watching this with interest.

May be unrelated but as I was measuring new brass against some fired Hornady ammo I thought to check the base to shoulder on some remaining unfired Hornady black box. The base to shoulder was considerably shorter on the unfired ammo than the virgin brass and varied quite a bit.

Maybe the ammo wasn't snug in the chamber?

 

[Mark611]

I have shot maybe 4 boxes of the Black with the 123ELDM's out of my AR rifles, and I was not happy with the accuracy, even my hand loads before AR Comp was used were not great with the 123 or 120gn ELDM's, now I do have a bunch of both loaded with AR Comp to test, but my barrels seem to like the Sierra 120gn Match Kings the best I haven't tried 123gn SMK's, I have a few other bullets to test in the 2 rifles I have been shooting, I also have 2 new barrels I'm going to be testing soon when I get them back from being MELONITED, to see what they will do, I'm kind of a BC guy when it comes to bullet selection, so I'm hoping to find a hi BC 123gn pill that will shoot as tight as the 120gn SMK's have from my barrels.

 

[misser]

I wouldn't assume over pressure based simply on what you've described. The factories have rigorous measures in place to ensure their ammunition adheres to SAAMI spec. There's too much liability to not do so. And "flat" primers are probably the most unreliable pressure sign in the handloader's toolkit. Nor is the spot where a semi-auto ejects its brass much of an indicator of anything.

Chrono data would give you more insight.

i dont question if the box of the black box was very high pressures. i know it was as i have been loading my own for 50 years .no oil in bore ,clean and dry. i would take one apart which really would not tell me much .

once in the past with a 708 american whitetail 139gr one box shot great then a different box different lot number did not shoot good at all .took one of each apart weighed the powder the difference was 9/10 . i can not swear it was the same powder yet it did look as tho it was the same stuff . then took all of that box ,took them apart and reloaded to match the good box . i was right .it fix'ed it

 

[misser]

I have shot maybe 4 boxes of the Black with the 123ELDM's out of my AR rifles, and I was not happy with the accuracy, even my hand loads before AR Comp was used were not great with the 123 or 120gn ELDM's, now I do have a bunch of both loaded with AR Comp to test, but my barrels seem to like the Sierra 120gn Match Kings the best I haven't tried 123gn SMK's, I have a few other bullets to test in the 2 rifles I have been shooting, I also have 2 new barrels I'm going to be testing soon when I get them back from being MELONITED, to see what they will do, I'm kind of a BC guy when it comes to bullet selection, so I'm hoping to find a hi BC 123gn pill that will shoot as tight as the 120gn SMK's have from my barrels.

the first ammo i shot in this 6.5 G was the hornady 123 SST it was bad , 3'' groups . then later put on a EC Tuner. same ammo ,3 to one spot and i do mean one spot, there was one hole

 

[Mark611]

My rifles are not match rifles with anything other than what they came with from the Manufacture, my 24'' is a Sanders upper, Beast set up 24''HB 1&8 twist, standard flash hider from Sanders, with my hand loads, 3/4'' groups like I said @200m, my 18'' is a BCA 1&8 twist with their flash hider will shoot 1.5'' @200m, it's hindered by my optic, it's a tactical scope with a dot reticule that covers up my 1.5'' bulls eye at 200m, can't see it! if it was a fine cross hair optic? I bet the groups would be a lot tighter, not to argue here, if you have been reloading for 50yrs? I think you need to evaluate certain things; Factory ammo should not be pressure spiking unless it's either bad ammo or something is amiss with the rifle? I have never had to use a tuner break on anything I have shot! maybe your barrel is bad? bore might be too tight? don't know, your rifle, IMO if you are using a tuning break? it sounds like you also have a harmonic issue with your barrel?

 

[misser]

My rifles are not match rifles with anything other than what they came with from the Manufacture, my 24'' is a Sanders upper, Beast set up 24''HB 1&8 twist, standard flash hider from Sanders, with my hand loads, 3/4'' groups like I said @200m, my 18'' is a BCA 1&8 twist with their flash hider will shoot 1.5'' @200m, it's hindered by my optic, it's a tactical scope with a dot reticule that covers up my 1.5'' bulls eye at 200m, can't see it! if it was a fine cross hair optic? I bet the groups would be a lot tighter, not to argue here, if you have been reloading for 50yrs? I think you need to evaluate certain things; Factory ammo should not be pressure spiking unless it's either bad ammo or something is amiss with the rifle? I have never had to use a tuner break on anything I have shot! maybe your barrel is bad? bore might be too tight? don't know, your rifle, IMO if you are using a tuning break? it sounds like you also have a harmonic issue with your barrel?

yes its a harmonic issue , the tuner fixes it . enough time, bullets ,powder and moving bullets in and out of the case it can be worked out to get intended accuracy . tuners can shorten that trip . using the tuner with that black ammo box ,i had it with 9 rounds . win win

 

[dellet]

Flat primers also come from excessive headspace, factory ammo and new brass is notorious for being short.

The 2 o’clock ejection is a sign of too fast of bolt speed, over gassed. Not necessarily high pressure.

A slower powder, producing the same velocity, generally generates more muzzle pressure, and faster bolt speed.

Swipes and brass flow into the ejector pin hole would be more associated with high pressure.

 

[Minshooter]

Had some of that same ammo a couple years ago.
First time at the range, was blowing out primers and, in my opinion, showing major over pressure signs,
(as in, completely loose primers, falling out of the case, with blackened primer pockets).
-Didn't notice until I picked up the brass, which was ejected off the table, onto the ground.
Had just previously fired some other types of factory ammo, which all fired perfectly normal.
Didn't have a chrono along at the time, and will never fire a single additional round to test.
Headspace, fired brass from other ammos, etc. all checked out normal.

Contacted Hornady (Phone call); they said I could send the ammo to them, at my expense, and if
it didn't test within their specs, they would replace it; otherwise they would return it, at my expense.
I believe I said "Forget it", or maybe some other words (started with an F, anyway).
Have not purchased any Hornady factory ammo since.

Really do like their dies, though.

 

[misser]

Flat primers also come from excessive headspace, factory ammo and new brass is notorious for being short.

The 2 o’clock ejection is a sign of too fast of bolt speed, over gassed. Not necessarily high pressure.

A slower powder, producing the same velocity, generally generates more muzzle pressure, and faster bolt speed.

Swipes and brass flow into the ejector pin hole would be more associated with high pressure.

odd , the new brass max charge H335 i loaded did not kick the brass forward but out to 4 o clock not one of the powders i used sent them forward

 

[Laurie]

Flat primers also come from excessive headspace, factory ammo and new brass is notorious for being short.

Yes, this seems to be a feature of 6.5 Grendel brass. I was puzzled and rather worried by the behaviour of two batches of initial handloads in a new Howa Mini. One (IMR-8208) had tight bolt lift even with the starting charges and witness marks from an over-tight (case-head to shoulder) case fit in the chamber, but with perfect primers lacking any pressure indications. The other (Ramshot TAC) had low case expansion, but flat as a pancake fired primers.

After mulling this over, I decided to check new unfired cases and both lots of fired ones on the 'headspace' comparator (not headspace rather case shoulder-position comparator). There was an 11 to 12 thou' difference between unfired (new Lapua) cases and those fired with 8208; ca. half that from the TAC loaded examples. What seemed to have happened was that the full case worth of the bulkier 8208 had rammed the shoulder forward really far and hard creating a longitudinally tight case fit and hard primary extraction. TAC had only part-fireformed the case and produced the classic flat primer of an excess headspace condition. Looking around forums suggested this shoulder position being too far back was the norm with new 6.5G cases.

Since then, I've treated all first firings of my (very expensive) Lapua 6.5G cases as if this was a wildcat number type fireforming with the bullet well into the lands keeping the case-head hard on the bolt.

 

[misser]

Yes, this seems to be a feature of 6.5 Grendel brass. I was puzzled and rather worried by the behaviour of two batches of initial handloads in a new Howa Mini. One (IMR-8208) had tight bolt lift even with the starting charges and witness marks from an over-tight (case-head to shoulder) case fit in the chamber, but with perfect primers lacking any pressure indications. The other (Ramshot TAC) had low case expansion, but flat as a pancake fired primers.

After mulling this over, I decided to check new unfired cases and both lots of fired ones on the 'headspace' comparator (not headspace rather case shoulder-position comparator). There was an 11 to 12 thou' difference between unfired (new Lapua) cases and those fired with 8208; ca. half that from the TAC loaded examples. What seemed to have happened was that the full case worth of the bulkier 8208 had rammed the shoulder forward really far and hard creating a longitudinally tight case fit and hard primary extraction. TAC had only part-fireformed the case and produced the classic flat primer of an excess headspace condition. Looking around forums suggested this shoulder position being too far back was the norm with new 6.5G cases.

Since then, I've treated all first firings of my (very expensive) Lapua 6.5G cases as if this was a wildcat number type fireforming with the bullet well into the lands keeping the case-head hard on the bolt.

have ever sized a brass,sliped it into the chamber and let the bcg slam shut , then rechecked the measurement of the brass ? shorter ?