Chamber OAL

[Rickc]

How many here have checked their chamber overall length.

I always do this with all my rifles with whichever bullet I choose to use.

Anyway when I checked my new JP barrel with the 123gr Amax I found it to be 2.272

Seems that the grendel has a pretty short throat.

I would be interested to see what others have found for this measurement

[SDguy]

Are you actually asking about seating depth relative to the base?

Are you actually asking about seating depth that allows the oagitive to just touch the lands?

[ricsmall]

How many here have checked their chamber overall length.

I always do this with all my rifles with whichever bullet I choose to use.

Anyway when I checked my new JP barrel with the 123gr Amax I found it to be 2.272

Seems that the grendel has a pretty short throat.

I would be interested to see what others have found for this measurement

That sounds about right. It will vary by .008"-.010" even in saami chambers from what I've seen. Not with the same reamer, but different Reamers that are all saami. It's not a short throat, it's the tapered freebore as opposed to parallel freebore in a conventional throat.

Richard

[Rickc]

Are you actually asking about seating depth that allows the oagitive to just touch the lands?

stoney point OLG

[cory]

IMO 2.29" max COL is ideal for the 123gr Amax/SST I'd be happy with anything from 2.27" - 2.31". Pushing it another -0.01 +0.025 tolerance if the barrel holds 0.5 moa or better.

Using the Forster gauge.

PF Bartlein 16"
Bullet Weight (gr) MAX OAL (in) COL (in)
Hornady SST 123 1.728 2.325
Nosler HPBT 123 1.756 2.297
Hornady BTHP 140 1.730 2.340
Hornady SST 140 1.730 2.360
Nosler Btip(H) 100 1.747 2.305
Barnes TTSX 100 1.765 2.335
Barnes LRX 112 1.741 2.365
Barnes LRX 127 1.741 2.365
Nosler Accubond LR 129 1.771 2.430
Berger Hybrid Tactical 130 1.747 2.381
Hornady Vmax 95 1.725 2.282
Sierra Varminter 85 1.765 2.214
Cerberus 90 1.709 2.330



Lilja 11.5"
Bullet Weight (gr) MAX OAL (in) COL (in)
Hornady SST 123 1.707 2.304
Nosler HPBT 123 1.748 2.289
Hornady BTHP 140 1.718 2.328
Hornady SST 140 1.717 2.347
Nosler Btip(H) 100 0.558
Barnes TTSX 100 1.763 2.333
Barnes LRX 127 0.624
Nosler Accubond LR 129 1.762 2.421
Berger Hybrid Tactical 130 1.723 2.358
Hornady Vmax 95 1.698 2.254
Sierra Varminter 85 1.755 2.205

Hornady Gauge

PF Lilja 24" (It's a short chamber, but it shoots to well to mess with.)
Bullet Weight (gr) MAX OAL (in) COL (in)
Hornady SST 123 1.665 2.241
Nosler HPBT 123 1.709 2.230
Hornady SST 140 1.685 2.304
Nosler BTip(H) 140 1.724 2.268
Nosler Btip(H) 100 1.701 2.235
Barnes TTSX 100 1.729 2.274

[Rickc]

Well I am jammed into the lands at a COL of 2.270 with the 123 Amax.

The SST 2.272 within 2 thousands of the amax

[cory]

You should be fine running factory.

My Lilja with the short throat loves a 0.025-0.015 jump to lands. If I was you I'd load at 2.25 +0-0.1 and see how well she'll shoot.

[Rickc]

You should be fine running factory.

My Lilja with the short throat loves a 0.025-0.015 jump to lands. If I was you I'd load at 2.25 +0-0.1 and see how well she'll shoot.

Don't run any factory ammo. I reload everything.

I picked 2.255. that is only a 0.015 jump.

I did a little test because those Amax are sitting pretty deep in the case. I used the book COL 2.245 and the max charge 31.2 gr of CFE223 and then pulled that bullet and the powder was compressed into a clump. Decided then that I needed a longer COL.

So with the longer COL I believe I will be safe to run from 30gr to 31.2 grains in 0.3 grain increments and see what it likes. Then we will play with seating depth.

[cory]

Do you have a vibratory cleaner? Load your powder, set your bullet into the case to prevent spilling powder, then take the case full of powder and hold it in contact with cleaner while it's running for about 5 - 10 seconds each. You'll be amazed at how much further the powder settles and how much more room you have.

There's a good discussion on this technique in a thread somewhere on this forum.

Edit: I've seen video of guys using electric toothbrushes too.

[LRRPF52]

How many here have checked their chamber overall length.

I always do this with all my rifles with whichever bullet I choose to use.

Anyway when I checked my new JP barrel with the 123gr Amax I found it to be 2.272

Seems that the grendel has a pretty short throat.

I would be interested to see what others have found for this measurement

Mag length COL for AR15 has been 2.260" for decades. You can get some that are a little longer, but as you push the limitations towards the edge of the mag body, you increase the likelihood of hanging up on the magazine.

The 6.5 Grendel was designed to work within the AR15 magazine well and easily-manufactured magazines with standard COL.

[Rickc]

Mag length COL for AR15 has been 2.260" for decades. You can get some that are a little longer, but as you push the limitations towards the edge of the mag body, you increase the likelihood of hanging up on the magazine.

The 6.5 Grendel was designed to work within the AR15 magazine well and easily-manufactured magazines with standard COL.

Magazine length has nothing to do with what I am talking about

You still need to know your max chamber length to the lands. Trust me there are bullets that will jam into the lands even loaded mag length.

Many of.my most accurate loads are with berger vld's jammed 1 to 2 thousands into the lands. Always over mag length and single loaded. If I didn't know where the lands were this would not be possible.

[JASmith]

Magazine length has nothing to do with what I am talking about

You still need to know your max chamber length to the lands. Trust me there are bullets that will jam into the lands even loaded mag length...

I do not agree with that characterization.

The only time one wants to push the SAAMI-spec 2.260" is if you plan to single load an AR or one is using a bolt or single shot that tolerates longer overall lengths.

That makes the maximum cartridge length the lesser of two numbers:

• The SAAMI spec 2.260" or
• The length where the bullet kisses the lands.

The lengths posted so far are consistent with others' experience, including my own. To be sure there are differences among the population but they are largely within what one expects with items produced literally around the world.

[Rickc]

I do not agree with that characterization.

The only time one wants to push the SAAMI-spec 2.260" is if you plan to single load an AR or one is using a bolt or single shot that tolerates longer overall lengths.

That makes the maximum cartridge length the lesser of two numbers:

• The SAAMI spec 2.260" or
• The length where the bullet kisses the lands.

The lengths posted so far are consistent with others' experience, including my own. To be sure there are differences among the population but they are largely within what one expects with items produced literally around the world.

I don't think you understand what I said.

I single load.ar's all the time and I shoot them jammed into the lands 1 to 2 thousands. It's very common. If you haven't measured your chamber length then you can't possibly know where the lands are.

Also there are many bullets out there that if you load to a COL of 2.26 the bullet will strike.the lands.and.the.bolt won't even close.

You have to measure the chamber length with each bullet you use. I use the stoney point overall length gauge.

I am sure you can use book COL's and be fine but for accuracy seating depth is just as important as powder charges.

[VASCAR2]

I checked four different 6.5 Grendel barrels with my Hornady lock n load gauge with the 123 grain A-Max. The barrels in order checked were 16" J&T chrome moley 2.267, 18" Brownell's SS SAAMI chamber (1st batch short chamber) 2.241, 20" Shilen SS 2.296 and 22" Lothar Walther SS 2.275.

[Rickc]

My JP with the 123 Amax is 2.272