Bolt Action Grendel

[AFRO408]

Grendel bolters becoming more popular! I won't feel so alone at home anymore.

Hi gents, its a good source of Grendel info here. I'll get back to you about that reamer later on tonight.

I went out yesterday with the shortened PacNor and the more I shoot it, the better it seems to perform. Can you tell which shot I pulled? Need to buy some more BM1 when I head up for the SHOT show in Sydney.

[ATTACH=CONFIG]1544[/ATTACH]

Nothing wrong with that group Adam. Short barrels, combined with short cartridges, work well, eh.

[eljefe]

Sambar- Asking because of all the 6.5 & 'Elk interest'
Von G-Yup, would be a nice way to blood my 404.Got some interesting 350 gr GC CB to check out...
Ready when you are, Tony!
Adam, tha'ts a splendid effort.
... looks like I want my Grendel right now. So BM1 is in?Am still looking for Lil Gun ( for the 'Juice')

[Von Gruff]

1. I'll probably get a Walther bbl for it. Maybe a TSE. Don't know yet.

Tony, What do you think of the TSE barrels. I have a couple and while they are very good shooters I do find the fouling to be a little more than I would have expected.

Von Gruff.

[adamjp]

I need to get some more BM1 and work it up a little more. I think there is another half to full grain in it before pressure is an issue. Should get those Scenars out at nearly 3000fps - 2950 may be good.

I did do some workups with the 100gn NBTs over BM1 and manged to get them going at just over 3000fps (3043 IIRC) but I felt the brass was getting smashed a little hard. SD and ES numbers were single digit though.

One thing I have learnt is that what works in an AR15 Grendel is not always the best thing in a bolt Grendel. Still exploring this so I'm not confirmed on it yet.

[eljefe]

Adam, there's the other bloke on AHN, who 's running a bolt Grendel, he used a quote Grendel reamer from PTG unquote, any idea whether its a bolt or AR reamer? He's running 2207.
Cheers

[adamjp]

Yes, Andrew has put one set of loads down the tube on his m85 based Rifle. He is still waiting for his gunsmith to finish the rest of the rifle so he can work it some more.

His load of 2207 behind the 120gn Sierra ProHunters will only be delivering around 2400fps. Lots of room for development. FWIW he is using an A&B barrel.

No idea on his reamer specs, it was a new order from PTG when the first one got smashed in a tight spot of the A&B barrel.

[AFRO408]

Tony, What do you think of the TSE barrels. I have a couple and while they are very good shooters I do find the fouling to be a little more than I would have expected.

Von Gruff.

I have been fitting TSE barrels since the late 90's and haven't had one come back as being faulty. Sure some of them foul up a bit, but if they look rough to me, then I run a lapp through them and they are fine then. If you know how to hand lapp, then do that, otherwise I would suggest that you shoot a couple of hard cast bullets, rolled in fine lapping paste, through them. That should fix the problem. Or give the bores a rub with Butches Bore shine. I'm told that that works as well.

The worst fouling barrel, I have fitted, was a Douglas CrMo .243, requested by the customer. Cost him $150 more and the throat was totally fouled up in two weeks. He was a pro 'roo shooter and didn't know how to clean a barrel either. He was really disappointed. I wonder why??

[LRRPF52]

I was just speaking with the guys from Lapua at a Wilderness Expo here in Finland, and one of them has a Sako 85 chambered in Grendel, with a varmint profile barrel. I did a major double-take when he said he's getting 940 m/s (3084fps) with the 123gr Scenar using N550. I made sure I understood him correctly as I took out the calculator function in my phone. They said it was a 600mm barrel, which is 23.6" long.

I asked if he was using a longer COAL, and he said he's uing the Lapua load manual recommended COAL.

[adamjp]

I was just speaking with the guys from Lapua at a Wilderness Expo here in Finland, and one of them has a Sako 85 chambered in Grendel, with a varmint profile barrel. I did a major double-take when he said he's getting 940 m/s (3084fps) with the 123gr Scenar using N550. I made sure I understood him correctly as I took out the calculator function in my phone. They said it was a 600mm barrel, which is 23.6" long.

I asked if he was using a longer COAL, and he said he's uing the Lapua load manual recommended COAL.

Wow!!!! I'd like to see the pressure trace from a pierzo on that! That is a max load in my 6.5x47 Lapua - with 38.x gn of AR2208 (Varget).

I thought I was pushing it with a 108gn Scenar at that speed.

If you could ask him very nicely for some boltgun loads I would certainly appreciate it.

[Buck2732]

Wow!!!! I'd like to see the pressure trace from a pierzo on that! That is a max load in my 6.5x47 Lapua - with 38.x gn of AR2208 (Varget).

I thought I was pushing it with a 108gn Scenar at that speed.

If you could ask him very nicely for some boltgun loads I would certainly appreciate it.

Plus one for me too please.

[LRRPF52]

I keep thinking back on the conversation I had with him, and the only thing that makes sense for me is if he was talking about .260 Rem, but I was certain we were talking about the Grendel, as he said he has 2 Grendels, and at least one was a bolt gun, and he's getting 940 m/s with the 8 gram Scenar out of it.

[hm2 clark]

Someone remind me please, "How much pressure does the the CZ 527 tolerate?" and "How much pressure does the Grendel generate?"

[adamjp]

You may well be onto something there.

He may also have been talking about the 6.5x47 Lapua - a great case that equals the 260 Rem with bullets in that weight range. It is also capable of withstanding extreme pressure better than most. The 6.5x47 Lap has a H2O capacity of 48gn, the 260 54gn (but it loses more with seating the bullets deeper). IIRC the Grendel is fully 10gn under the 6.5x47 Lap case.

3080fps is quite doable out of a 24in barrel with the 6.5x47 Lap case and a 123gn Scenar. Stiff, but doable.


I just can't see those velocities with the Grendel case. Not if you want to extract it anyway. The CZ action, or the Mini Zastava are good, but their qualities are immaterial as the brass will liquify at pressures needed to drive a 123gn Scenar at 3080fps from a little Grendel case.

[JASmith]

Someone remind me please, "How much pressure does the the CZ 527 tolerate?" and "How much pressure does the Grendel generate?"

adamjp has indicated that "The CZ action, or the Mini Zastava are good, but their qualities are immaterial as the brass will liquify at pressures needed to drive a 123gn Scenar at 3080fps from a little Grendel case."

So to complete the answer to your question, the targeted pressures for standard AR bolts are around 50,000 psi. This pressure level is set to assure very long and highly reliable bolt life. We have also been just told that the Grendel case, on the other hand, is designed for 58,000 psi.

The extra 8,000 psi or 16% pressure, has a significant impact on attainable muzzle velocity.

[adamjp]

That it does, but I would estimate the pressures needed to throw a 123gn at those speeds from the Grendel case will be closer to 80k PSI. Only guessing mind you, someone with Quickload could help on this theory. My 6.5x47 Lap will achieve those speeds at the 65k PSI limit of that cartridge, just.

At pressures above 75k PSI brass flows like liquid and would probably lock the action up on both the CZ and the Mini Zastava when it flowed into the ejector slot.

Oddly the actions are probably able to contain pressures towards 90k PSI, although I'm not sure how it would look afterwards or how useable it would be.