6.5 Grendel Bolt rifle

[GSPV]

You'd best listen to Mike about the Grendel-based family of cartridges. He knows what he's talking about. By actual experiment, not by guesswork.

You could listen then, perhaps, find a way that he's wrong. Maybe. But if you ignore what he's saying and it blows up in your face, you have no one but yourself to blame.

 

[dolek]

6.5 Grendel Bolt rifle

 

[GSPV]

Have at it. Great cartridge. I've been thinking about building one for my daughter who is small-framed. Going to start her with a 22-100 to see how she handles that.

Start with an AR load, and then work up til you start to get sticky bolt lift, marks on the bottom, etc, then back off from there.

I shot a 30 Major, a Grendel necked up to 30 for a long time in IBS Score. As did many others. Mike got me onto it. That must have been ten years ago now. Best, most accurate rifle that I ever owned. Another guy has it now and is doing well with it.

Btw, I never saw anything wrong with my Grendel brass. I shot it on the edge quite a bit, too.

Addendum for clarity: I shot the 30 Major in a full custom bolt gun. 30.4 grains of N120 was its happy place. 30.8 was borderline hot, but shot great.

 

[spclark]

Btw, I never saw anything wrong with my Grendel brass. I shot it on the edge quite a bit, too.

As did I, at least for a short time.

Caught the Grendel bug ~ 13 years ago, outfit in Texas was marketing match uppers fitted with Walther barrels. For awhile when I was searching for loads I could depend on at that outfit’s owner’s suggestion I bought some N530.

When one afternoon I noted a batch of AA brass being ejected bearing what I can only describe as a ‘belt’ (as in 300WM) I quit shooting.

Later discussions w/ Bill Alexander suggested pressures to effect that kind of brass movement had to be upwards of 80,000 psi. No separated case heads, no split cases, no failure to extract (rims torn off), no broken bolt lugs.... Gave up on 6.5 Grendel (and 6RAT derivative) a couple of years later out of frustration with failure-to-feed issues I couldn’t get resolved.

Took up with 6HAGAR, which I still shoot.

I discovered Pressure Trace System a couple of years ago, proved invaluable with developing loads for a 7mm, 308WIN case-based wildcat I started messing with for long range bolt gun.

 

[gunsandgunsmithing]

As did I, at least for a short time.

Caught the Grendel bug ~ 13 years ago, outfit in Texas was marketing match uppers fitted with Walther barrels. For awhile when I was searching for loads I could depend on at that outfit’s owner’s suggestion I bought some N530.

When one afternoon I noted a batch of AA brass being ejected bearing what I can only describe as a ‘belt’ (as in 300WM) I quit shooting.

Later discussions w/ Bill Alexander suggested pressures to effect that kind of brass movement had to be upwards of 80,000 psi. No separated case heads, no split cases, no failure to extract (rims torn off), no broken bolt lugs.... Gave up on 6.5 Grendel (and 6RAT derivative) a couple of years later out of frustration with failure-to-feed issues I couldn’t get resolved.

Took up with 6HAGAR, which I still shoot.

I discovered Pressure Trace System a couple of years ago, proved invaluable with developing loads for a 7mm, 308WIN case-based wildcat I started messing with for long range bolt gun.

I would guess it was opening too early. The brass is solid for about .150".

What was the load?

 

[GSPV]

SPClark:

I still have a 30 Major AR. Left over from the IBS foray into an AR class. Mike set it up for me. I load *exactly* what he told me to load. I have not changed anything. Not even 1/10 grain of powder.

I'm good with bolt guns, but that AR stuff is too much black magic, no pun intended, for this country boy.

That AR was the worst thing that I ever did. It's super nice. 100% highest quality components. Just no bling-bling. Can't sell it for even half what I have in it. I've killed some varmints with it. I drag it out once in a while to beat the crap out of one of the camo-pants-and-black-tee-shirt crowd at the local range. Other than that, it's a danged safe queen.

 

[gunsandgunsmithing]

SPClark:

I still have a 30 Major AR. Left over from the IBS foray into an AR class. Mike set it up for me. I load *exactly* what he told me to load. I have not changed anything. Not even 1/10 grain of powder.

I'm good with bolt guns, but that AR stuff is too much black magic, no pun intended, for this country boy.

That AR was the worst thing that I ever did. It's super nice. 100% highest quality components. Just no bling-bling. Can't sell it for even half what I have in it. I've killed some varmints with it. I drag it out once in a while to beat the crap out of one of the camo-pants-and-black-tee-shirt crowd at the local range. Other than that, it's a danged safe queen.

This thread has already gone "AR sideways, I guess one more won't hurt.

The reason behind the design of my 30 Major(Grendel) cartridge was to make major power factor in USPSA three gun competition in an AR15 rifle, to take advantage of the scoring advantage of shooting major. It does that quite well, as evidenced by the success of the USAMU Team with it.

The reason I bring this up is to ask if Parker is still shooting run and gun. If so, it'd be great for him.

That said, I've always been an accuracy minded man, first. When developing the cartridge and data, I was very impressed by how accurate the cartridge is. I immediately had a match reamer ground for bolt action rifles and began testing. WOW! I've competed with it in BR ever since, with some success and the world record 5 shot group at 100 is held by the same basic cartridge, to this day. That group is .0077" after all measurements for record.

 

[spclark]

What was the load?

No idea. I’m not the best note-keeper & this was at least 12, maybe 13 years (and one full, uproot-after-37-years move) ago. Sorry.

 

[gunsandgunsmithing]

No idea. I’m not the best note-keeper & this was at least 12, maybe 13 years (and one full, uproot-after-37-years move) ago. Sorry.

I understand.

 

[Ksmirk]

gunsandgunsmithing by no means did I intend to come across as I thought you were full of it but from the little I've gotten to mess with this round it seems rather fast from the little info I've got so far. I've spoken off and on several times with the gentleman who is chambering my barrels and he has mentioned that there is a lot the little round can accomplish.

Today it seems everyone is wanting to one up the other guy and that's the reason I don't put much faith in what I read these days unless I get to know a person but I hope nothing personal came from my post, I really don't know who you are or what you know just from my side those velocities seem a touch high from the little time I've been dealing with the round but I will agree that when I joined up the information was a lot better.

Kirk

 

[gunsandgunsmithing]

gunsandgunsmithing by no means did I intend to come across as I thought you were full of it but from the little I've gotten to mess with this round it seems rather fast from the little info I've got so far. I've spoken off and on several times with the gentleman who is chambering my barrels and he has mentioned that there is a lot the little round can accomplish.

Today it seems everyone is wanting to one up the other guy and that's the reason I don't put much faith in what I read these days unless I get to know a person but I hope nothing personal came from my post, I really don't know who you are or what you know just from my side those velocities seem a touch high from the little time I've been dealing with the round but I will agree that when I joined up the information was a lot better.

Kirk

There are no hard feelings on my part with you. The other guy followed me around contradicting everything I said. I put him on my very select "ignore list". He is only the 1st or 2nd person that I've used that function for.

I think if you talk with Bart or Billy Stevens about the 6 Grendel, they'll corroborate my findings of 3,400fps with 80's. As I said, those are very much MAX loads. From speaking with Bart, I think they saw similar speeds but with poor brass life in the barrels they tested. I can believe that. They are shooting their's at around 3,250, from what he told me. I'm not advocating for that load to be shot, but in my barrel, it seems to hold up and shoot well. Brass is good so far, with 5-6 firings on the test brass in my 6 Grendel.

In my 30 cal version, I've shot the same load for 11 years. Most of that time with a tuner. That load is a 110-118 gr bullet at 2,950-3,000 fps, depending on barrel and bullet. I've shot it faster but brass life was shorter and the load I've stayed with for so long has shot very well with very good brass life. Again, those are in my bolt action BR rifle.

I'm intimately familiar with the 30. It's proven itself to me over and over again. I tried my BR match load in an AR and it broke the bolt on the first firing. It was an AA bolt. FWIW. In my bolt gun, I've gone 50 firings of that load on Lapua Grendel brass. I figure I've fired north of 50,000 rounds of that load since I started with it. That's based on how many barrels I've shot out since then and barrel life is very similar to a 30BR.

FWIW and not looking at any useless AR data, all else equal, a 6.5 cal 80 gr bullet can be fired with LESS pressure and equal speed as a 6mm 80 gr. Piston area and expansion area are why. So, if you're talking strictly 6.5 cal, I don't think you'd have major pressure issues at all. ALL ELSE EQUAL.

BTW, I did blow a bolt gun up when doing my early testing. This is with the 30. It was an accident rather than a methodical part of pressure testing. I had two powders out and the phone rang! You can figure out the rest. The interesting part is that I WAS doing pressure testing when it happened. The Pressure Trace read 123,000psi!!!
It was done on a Remington action, with a 308 boltface and a Sako extractor...Worst case scenario! The three rings of steel worked and contained the vast majoity of gas as well as the Sako extractor. Keep in mind, I use .003-.005" clearance at all areas of bolt to barrel clearance. I got a few speckles of brass in my face and thankfully, I was wearing glasses or I wouldn't be reading this.

Here's a pic of the case. The Sako extractor was captive and did NOT come flying out. The case blew out at the ejector hole. I'm a big advocate for cutting tenon dimensions for what I believe are PROPER bolt clearances...as you can imagine. I read years ago that Mike Walker's original design for the three rings of steel concept were .003-.005 at all surfaces. I can't say that it would or would not have failed with more clearance, but after what most would call a worst case scenario "blow up", I'm a big believer.

 

[ASbobcat]

Question about Lapua brass at bolt gun pressures (59K-62KPSI) in 6.5 or 6mmGrendel. How much trimming have you had to do, and/or what is your average case length growth per resizing cycle? How many usable reloads?

Thanks

 

[gunsandgunsmithing]

Question about Lapua brass at bolt gun pressures (59K-62KPSI) in 6.5 or 6mmGrendel. How much trimming have you had to do, and/or what is your average case length growth per resizing cycle? How many usable reloads?

Thanks

I've never quantified that exact number but I can tell you that brass stretch has mostly to do with how much your die sizes your fired brass. So it's a relationship between the two that is mostly responsible for this figure...not the cartridge. The idea being that your die sizes the brass, diametrically, as little as possible, yet yield a round that chambers and extracts easily for several firings without any trimming. Of course, your chamber length vs virgin brass also come into play but what I think you are asking is best answered by what I have said already. This is why there are custom dies, in the first place. It's not(or shouldn't be) because of any reason other than how much the brass gets sized. Also, that number is dependent upon the chamber size and you(I) can just as easily spec a chamber reamer to work with a die as a die maker can spec a die to work with a given chamber reamer Either way, you wind up at the same place. Minimal brass growth is dependent upon how much you move the fired brass. Don't overthink this. A resize die has a very basic and simple job but is dependent upon the chamber size. I can say, to your original question, that I trim my brass once after initial firing forming, for about 25 firings, at about the midway point. If it needs it again, it was tired anyway and I just make new brass. Without regard to some of the new brass makers that claim to be of comparable quality to Lapua...Lapua is the cheapest brass on the market, as long as you don't lose it due to the number of firings it yields vs the rest. It's not really even close..

In other words, if you're having excessive brass stretch, it's very likely that you are sizing the brass too much, diametrically. As for how hot I'm loading...pretty HOT. I lose primer pockets first, usually. Lapua Grendel brass is every bit as good as their 220 Russian brass used for a ppc...and requires little or no fire forming for a 6 or 6.5 Grendel chamber and has a tad more capacity than a ppc.

To put that into perspective, I typically shoot 68's at around 3,500fps and 80's at 3,350fps....with around 25 firings per case.

 

[68W40 Retired]

I shoot a semi-custom Howa Mini in 6.5 Grendel. I have found A2520 to be very accurate with 100gr Nosler Partitions at 2800fps and Alliant PPV moves the Sierra 85gr HPs along at 2900fps from my 22" barrel.

68W40

 

[rebel]

I have had a CZ 527 on backorder since last October. Haven't seen it yet. Got the scope, the mount, 100 pieces of Lapua brass, ect., ect. No rifle yet.

 

[Laurie]

I've never quantified that exact number but I can tell you that brass stretch has mostly to do with how much your die sizes your fired brass. So it's a relationship between the two that is mostly responsible for this figure...not the cartridge.

You really have to watch shoulder position with this cartridge. I was surprised to see a large discrepancy in readings of the 'headspace gauge' (really, case-gauge) after first firings of Lapua brass in a Howa 'Mini'.

IMR-8208XBR in mild, working-up loads produced a tight longitudinal case-fit after firing, enough for the bolt to produce a circular bolt witness mark on the case-head. Primers remained well rounded with no pressure indications at all. On the face of it, all charges including starting ones were producing over-high pressures on the bolt lift test

Cases used with Ramshot TAC with its lower case-fill than 8208 showed the reverse. Very easy bolt unlock, but with every primer hammered flat.

Measurements of cases with the Hornady 'Headspace gauge' showed a big difference in shoulder position from, the two sets of new once-fired brass, the 8208-cases with another three or four thou' over the Ramshot ones.

Mucho puzzlement until I measured new out of the box unfired examples. Shoulders were set around 9 to 10 thou' short of that from 8208 fireformed examples out of the factory rifle chamber. As the rifle was new and had just undergone British proof testing that includes a chamber gauge check, it seemed unlikely that the chamber is out of spec, rather that Lapua is making cases likely to produce a mild 'headpsace condition' on first firing. I can only assume that this is tied in to the cartridge's primary use being in ARs, many of them home assembled, and concerns about firing on near to but not 100% lock-up.

In any event, the resulting fireforming in the chamber may also produce that amount of case-stretch. Setting up the sizer die in the press in the touch the shellholder default position also pushes shoulders back too far for the Howa. As well as being a quick way to induce case separations, such sizing/firing will produce an excessive apparent case-length growth on each firing.

(Incidentally, the brass has suffered no ill effects from its initial fireforming and body stretch and those cases have had several subsequent firings without problems.) In future though, I'll measure the shoulder positions of new out of the box brass and if the condition is there treat the first firing as per wildcat fireforming with the case-head anchored on the bolt by jam seating the bullet.

 

[gunsandgunsmithing]

You really have to watch shoulder position with this cartridge. I was surprised to see a large discrepancy in readings of the 'headspace gauge' (really, case-gauge) after first firings of Lapua brass in a Howa 'Mini'.

IMR-8208XBR in mild, working-up loads produced a tight longitudinal case-fit after firing, enough for the bolt to produce a circular bolt witness mark on the case-head. Primers remained well rounded with no pressure indications at all. On the face of it, all charges including starting ones were producing over-high pressures on the bolt lift test

Cases used with Ramshot TAC with its lower case-fill than 8208 showed the reverse. Very easy bolt unlock, but with every primer hammered flat.

Measurements of cases with the Hornady 'Headspace gauge' showed a big difference in shoulder position from, the two sets of new once-fired brass, the 8208-cases with another three or four thou' over the Ramshot ones.

Mucho puzzlement until I measured new out of the box unfired examples. Shoulders were set around 9 to 10 thou' short of that from 8208 fireformed examples out of the factory rifle chamber. As the rifle was new and had just undergone British proof testing that includes a chamber gauge check, it seemed unlikely that the chamber is out of spec, rather that Lapua is making cases likely to produce a mild 'headpsace condition' on first firing. I can only assume that this is tied in to the cartridge's primary use being in ARs, many of them home assembled, and concerns about firing on near to but not 100% lock-up.

In any event, the resulting fireforming in the chamber may also produce that amount of case-stretch. Setting up the sizer die in the press in the touch the shellholder default position also pushes shoulders back too far for the Howa. As well as being a quick way to induce case separations, such sizing/firing will produce an excessive apparent case-length growth on each firing.

(Incidentally, the brass has suffered no ill effects from its initial fireforming and body stretch and those cases have had several subsequent firings without problems.) In future though, I'll measure the shoulder positions of new out of the box brass and if the condition is there treat the first firing as per wildcat fireforming with the case-head anchored on the bolt by jam seating the bullet.

Yessir, ive noticed it as well. The Lapua brass is a tad short out of the box. What's more..I have 3 different go gauges for a grendel, from two different makers and none of them measure quite the same. If I chamber to the shortest one, to address the brass, then the Redding die or shell holder will need to be trimmed to get any bump. Go figure.

 

[Spook]

......all this jabber gets me thinkin' about a 6.5GT for some model 7 actions I have layin' around.

 

[JASmith]

As one who has spent bunches of time with the Grendel, including a fair bit of Pressure Trace work, I can say it is a great cartridge — for what Bill Alexander designed it to do.

For the velocity freaks: Go to your ballistics calculatators and see what adding even a 100 fps to the muzzle velocity will do at 600 yards. Remember that drop is readily corrected when using a good range finder. Drift is the item that we find more challenging to correct for.

Then, compare drift with the same bullet for the Creedmoor or large case.

’Tis a lot better to use the bigger cartridge at comfortable pressures than to squeeze a few extra fps and risk your rifle, your face, and your hands from a KABOOM!

 

[Rtheurer]

Or Neck it down to 22 cal and run a 90 or 88gr bullet that keeps right up with the 6.5 Creed. At Half the Powder charge.