Dumb question time...

[daved20319]

So how much is too much, and how do you tell? I've read numerous posts here that say that by the time you see pressure signs with a Grendel, you're already in trouble. I have no desire to damage either myself or my rifle, but I also don't want to settle on some anemic loads, when a little more powder might get me bugholes without risking catastrophe. And yes, I'm well aware that the most accurate loads are usually not max loads, but there are exceptions to every rule. Plus the fact that published max may not actually be max for my particular setup. BTW, I'm shooting a bolt action, and I know that can make a difference, but again, how much and how do you tell? Thanks, guys.

[A5BLASTER]

Chronagraph. Work up your ladder over the graph and it will tell you when you hit max for your rifle when you see a spike or dump in velocity between powder charges.

Work up in small increments 2 to at max 3 tenths between each charge.

I like 5 rounds at each powder charge.

In my howa grendel I typically stat at 29 grains. I do 10 at that and get a base line then do 5 rounds each at 2 tenths increase till it find the max in my rifle.

Then I look at the node with the tightest sd and es and load 5 rounds at that setting and 5 rounds each at 5 thousands shorter then 10 thousands shorter then 15 thousands shorter.

This is what works for me in my bolt grendel.

Hope it helps sir.

[Bigs28]

This is just me. I start 10% below max working up in 0.3 grain increments. I use a chronograph. If i see a velocity spike or pressure signs on my brass i stop. My 3 barrels have never shown a pressure sign on the brass at the published max load. My chronograph has shown velocity spikes though.

[VASCAR2]

I respect Hornady, Hodgdon, VihtiVuori, Lovex, Barnes and Western data the most. To me it appears the lawyers have had effect on the data released by Nosler, Sierra and Speer. I don’t like it that the actual pressure of the loads are not listed with some data. Are the reported velocity with a specific powder charge actually 52,000 PSI or because of liability reasons is this testers data actually 15-20% less than SAAMI max of 52,000 PSI/CUP?


I always start low and work up and try to use a chronograph especially when working up towards max in a new gun. Even in 223 Remington you see different powder weights suggested as max. Many manufactures use test barrels and universal receiver where Hornady uses specific 6.5 Grendel rifles.

Alexander Arms listed data producing higher velocities but AA data is several years old. There have been issues where members have had bolt failures with IMR8208XBR powder where they thought they were using safe loads. I think an additional issue with the AR-15’s is the possibility of having to much gas which affects the guns timing. Having to much gas can cause additional wear on extractors and bolts.

I also like to ensure my cartridges are not to long where the bullet is jammed into the lands. I always proceed slowly if I change components or even different lots of powder.

[Lemonaid]

This link may help, I like it.

http://www.frfrogspad.com/loaddev.htm

The basic max is the sammi spec for case pressure. Some load data sites will give pressure readings like Accurate/Western powders page 55

http://www.accuratepowder.com/wp-content/uploads/2018/11/WPHandloading-Guide-7.0-Web-REV.pdf

Look at the load data from numerous places either go with the one you trust most or go with the average to get the max load. Speer load data seems to be a bit on the low side for some.
On my reloads I go by "Max published velocity = Max pressure". If my chronographed velocity exceeds what was published, even if the grains of powder are below what the stated max is I consider it over max.

One of my Drill Instructors said "There are no dumb questions, only dumb people asking questions!"

[grayfox]

Roger to all the above. This is science yes, but more art and not exact technology; carefulness, alertness and consistency count a lot...
Good load data books are a must.
A good chrony is a must.
Get the 2 Grendel Handbooks -- IMO also a must for s serious reloader.
Start low work up.
If you change any part of your current recipe (even the brass type, the primer type, or the powder lot#), you need to back off and start again.

And, I would add.... again my $0.02, it is not all that often that the actual max load will be the most accurate for your gun, for your cartridges. The barrel must tell you what it can do.

[BobinNC]

SAMMI Maximum pressure for the 6.5 Grendel: 52,000 psi (AR-15 bolt), 58,000 psi (case strength)

AS you can see you can go considerably hotter with a Grendel bolt action than you can with an AR15. How much hotter is open to debate, but max loads tested in an AR15, would certainly be "very safe" in a Howa mini action. But, and there always is a but, I'm not sure what an extra 50 or 75 FPS by loading hotter than AR15 Max is going to buy you in a 20" barreled Howa Mini. It certainly doesn't make it to the 6.5 Creedmoor class, and a extra 50-75 yds or so at long range is not a very big deal at all. And the little extra velocity does not improve it's killing power enough to move the Grendel into another bigger weight class.

What I'm saying is yes, you can load the 6.5 Grendel hotter in the Howa Mini, but all you will really achieve is some minor bragging rights, and very little noticeable gain in actual performance on live or paper targets. IMHO and YMMV.

[LR1955]

So how much is too much, and how do you tell? I've read numerous posts here that say that by the time you see pressure signs with a Grendel, you're already in trouble. I have no desire to damage either myself or my rifle, but I also don't want to settle on some anemic loads, when a little more powder might get me bugholes without risking catastrophe. And yes, I'm well aware that the most accurate loads are usually not max loads, but there are exceptions to every rule. Plus the fact that published max may not actually be max for my particular setup. BTW, I'm shooting a bolt action, and I know that can make a difference, but again, how much and how do you tell? Thanks, guys.

Dave:

Guess it is time for my periodic warning to new handloaders of the Grendel.

Do not exceed max loads found in legitimate reloading manuals produced by the major powder and bullet companies.

You may be able to go over in other cartridges but I do not recommend it with a Grendel or a 6 AR. You will not get much more velocity but will slowly weaken the frame and wear out brass much faster than normal.

Most of the accurate loads you find with any rifle are found at about the 75% to 90% load range.

LR55

[Happy2Shoot]

To all the people who say "lawyers this and that" stop it. The only thing that happened was modern engineering. Better equipment, more knowledge, gives better reloading data.

Reading primers, measuring case head expansion, and looking for case swipes are all bogus methods to determine maximum average pressure.

[Kswhitetails]

To all the people who say "lawyers this and that" stop it. The only thing that happened was modern engineering. Better equipment, more knowledge, gives better reloading data.

Reading primers, measuring case head expansion, and looking for case swipes are all bogus methods to determine maximum average pressure.

I agree with both perspectives. However, if you dismiss how some companies are a little too sensitive to "lawsuit by stupid" you're just as far off. This sensitivity does play a roll in the data released by every company, some more than others. To say it doesn't is as ignorant as Bernie on real world economic consequences.

I get you Happy, and you're right. But I also understand the interpretation of the data. How else, if all was actual data, would you account for companies apparent unwillingness to publish data that more closely reflects every other manufacturer, and what we are seeing on safe reloading benches around the world?

[Gusmeister]

Lots of good advice here. It took me a while to adjust to max pressure showing no signs in my Grendel AR. This forum and good reloading sources are very important.

Yet there is one more thing I have to emphasize. Some years back I developed a very nice load for my Win 30-06. 150 gr bullet doing 2,800 fps and pressure was never an issue (A Speer book load). Many hundreds of rounds later my dad bought a brand new Tikka in 30-06. When my very "safe" load was fired in his Tikka the bolt locked up every time and had to be pounded open. Well.... that didn't last long. I ended up reducing the load by a full 3 grains. The rifle loved it and, with 3 grains less powder, it shot 150 gr bullets to the same 2,800 fps.

My point is that reloading books/sources are not necessarily wrong but neither are they necessarily correct. It is simply not a black and white thing. I hold a great deal of value in this forum as ideas, problems and solutions are discussed. I found a chrono to be especially helpful. If a load is going "faster than it should" then the pressures are probably higher than they should be. CFE 223 is a good powder to start with (hard to goof up). I like 8208 better but made some mistakes learning its properties. Honestly, if you are chasing velocity in an AR Grendel you probably have either the wrong cartridge or the wrong rifle. Yet the 6.5 Grendel is a great cartridge for many things. I love it!

[daved20319]

Appreciate all the info and insights, guys. Most of it I was already aware of, but there's pretty much nothing in this facet of our hobby that doesn't bear periodic repetition. Just as a reminder, I'm NOT running an AR based Grendel, mine is the HB Howa Mini. And no, I'm not chasing velocity, but Gusmeister gave a perfect example, different guns behave differently, and the folks that publish load data aren't testing all the different guns out there. I think it's also fair to say that most of the published data is based on AR based guns, and I don't think anyone will argue that the bolt guns are stronger. Seems that if an ammo manufacturer can market Ruger specific loads for some of their revolvers, it should be possible to have separate loads and data for bolt action Grendels. Yeah, maybe it's pushing the envelope, but that's what handloaders have always done. If no one ever did, we'd all be shooting round balls from flintlocks, and the term wildcat would have a whole different meaning. Just sayin'...

But I digress (as usual ). So if I'm understanding everyone, the only real way of insuring safe loads with the Grendel is to use a chronograph (I do), and to limit my velocities to published numbers. And, obviously, start low and work up, of course, while watching that velocity. Again, appreciate the input, folks, and maybe one of these days soon I'll actually have some data of my own to post. Later.

[Fess]

Early in the Grendel's life, there was an overpressure problem with some Grendel rifles. This might be why some companies are so cautious.

The Grendel has an unusual compound or 2-angle throat. Bill Alexander explained that this was to maintain accuracy with bullets of varying ogive shapes. As it turns out, it is very sensitive to reamer wear. If the throat section of a Grendel reamer is too small from wear, normal in-spec ammo can get jammed into the lands and become overpressure. Now manufacturers know to keep a close eye on this section of the reamer. Les Baer got around this problem by using the more common straight freebore and 1-angle throat in the .264LBC, a near-clone of the Grendel.

[A5BLASTER]

Early in the Grendel's life, there was an overpressure problem with some Grendel rifles. This might be why some companies are so cautious.

The Grendel has an unusual compound or 2-angle throat. Bill Alexander explained that this was to maintain accuracy with bullets of varying ogive shapes. As it turns out, it is very sensitive to reamer wear. If the throat section of a Grendel reamer is too small from wear, normal in-spec ammo can get jammed into the lands and become overpressure. Now manufacturers know to keep a close eye on this section of the reamer. Les Baer got around this problem by using the more common straight freebore and 1-angle throat in the .264LBC, a near-clone of the Grendel.

I think you meant to say there was an over pressure problem with copycat, wannbe mutt 264 something are other chambered rifles.

But spot on with the sammi reamers company's are doing much better of keeping their tools good these days.

[Fess]

I think you meant to say there was an over pressure problem with copycat, wannbe mutt 264 something are other chambered rifles.

But spot on with the sammi reamers company's are doing much better of keeping their tools good these days.

Actually, no. Les Baer was making true Grendel barrels at first and paying the licensing fees to Alexander Arms. Prior to the SAAMI certification, a fee had to be paid to Alexander Arms. The chamber drawings were not available even on this site. The short-throat problem also occurred with some Liberty 6.5 Grendel barrels and probably some others. It was a long time ago, but I believe that a significant number of Liberty 6.5 Grendel barrels were re-reamed with a straight freebore. This is what prompted the "Grendel II" reamers.

If you look at the SAAMI drawing, the Grendel throat starts with a 1/2 degree taper, then changes to a 1 1/2 degree taper. With such shallow angles, it takes very little reamer wear to move the rifling much closer to the neck. If the SAAMI diameter tolerance of .002" is used rather than the length tolerance of .015", the rifling moves quite a bit before it looks like the reamer is out of spec.