OAL Issues

[JT45]

Hey Guys

I recently started reloading for my new Grendel build however have not shot any of the reloads. Kindy went ass backwards about it by loading 70 then using my Hornady OAL gauge and 6.5 modified case insert. The OAL is measuring 2.185 without the bullet inserts which can't be right? I'm only applying light pressure once I feel the bullet make contact with the rifling. So I went a step further and made a dummy round using new Lapua brass, Hornady 123 grain ELD and seating to exactly 2.26 using a Redding Comp Seating Die - Verified with my Calipers. I chambered the round and extracted using the charging handle. The projectile has deep scratches and the OAL grew slightly from 2.26 to 2.261. Attached are a few pics. Any words of wisdom? The barrel is a new JP Enterprise 22 Supermatch.

Appreciate any insight. I know JP has quality stuff but this bothers me.

Joey

[Kilco]

If your bullets are longer after extraction it seems you are definitely hung up on the lands. What about if you seat the bullets at factory ammo OAL 2.245-2.250? Any contact?

[Drillboss]

You didn't mention if the rounds are sticky to extract. How do factory rounds chamber and extract?

[bigdaddyflo]

Some of the "rotational" scratches may be from the round coming out of the magazine while being chambered. You might look at the chamber to see if there is a "yuge" piece of metal that may be scratching the bullet like that, but I doubt you'll find that to be the problem. May try loading one by hand (no magazine) and see what the end result is.
On the round growing in length, others have mentioned that you are probably into the lands - I agree. Use a sharpie marker on one of your rounds and paint the bullet. Chamber it, remove it and inspect it. You can measure the scratches and see how deep you are into the lands and make adjustments to your seating depth. Naturally don't load to max when working your load up!
Let us know what you find out!

[Boostmeister]

Hey JT, did you use a set of Go/No-Go gauges when you built this firearm? I know that my max OAL is controlled by the length of the magazine, not the chamber.

[JASmith]

It may seem strange that a factory bullet designed more or less expressly for the Grendel, can't be seated to full magazine length. Nonetheless it appears that Hornady has done that.

While I have not loaded the ELD, I have done a lot of the 123 SST.

First, the pictures in the OP show two bands of contact that I recognize. The one nearest the case mouth is contact with the throat. The smooth band near the tip appears to be from a very closely fitted seating plug. It looks like the die maker (Hornady?) made it for this bullet.

Cutting to the chase: My 123 gr SST factory loads are around 2.245" COAL. Further, the bullet just touches the lands at 2.245" so my handloads are held to that length. The chamber was cut with a Manson Grendel reamer.

The Hornady/Stoney comparator length is 2.2658 before subtracting the inch for the gage.

Loading to this length may still result in the "light kiss" Bill Alexander indicates is acceptable with the compound throat in the Grendel.

[LRRPF52]

The marks around the ogive near the mouth are from the rifling.

The mark nearer the tip is from the lugs of the extension.