700 AAC-SD 300BLK keyholing

[m4a1sof]

Did you contact Remington?

Before I go through the hassle of sending it in for warranty work, I want to bring it to a gunsmith and get his opinion after he checks the crown and barrel out. I'll post what he says, probably be next week though I have been covered up with work lately. Just sent my form 4 in a couple of weeks ago for the suppressor, so there is definitley no hurry to get it sorted out . My sot doesn't do the efile thing so I'm looking at probably ten months or more before it gets out of jail.

[firefuzz]

Did you contact Remington?

Before I go through the hassle of sending it in for warranty work, I want to bring it to a gunsmith and get his opinion after he checks the crown and barrel out. I'll post what he says, probably be next week though I have been covered up with work lately. Just sent my form 4 in a couple of weeks ago for the suppressor, so there is definitley no hurry to get it sorted out . My sot doesn't do the efile thing so I'm looking at probably ten months or more before it gets out of jail.

How did this turn out?

Rob

[m4a1sof]

Don't know, I still haven't had a chance to bring it to a gunsmith. If I can ever get over there, I will post the results.

[gunfan2]

I have the same gun, was the 220 grain blackout Remington ammo, the UMC stuff? I shot this stuff in mine and couldn't get it to group, bullets tore oblong holes. Turned around and shot some handloads of 220 grain SMK and seen little groups and tiny round holes. I sent 10 boxes of the UMC stuff back to Remington and they replaced it with the yellow/green box remington 220 grain sub loads and they then shot fantastic out of my gun.

[Red magnum]

Unfortunately I'm having the same issue with mine, the crown on the barrel looks fine tho.

Today I was using Hornady 208gr amax subsonic factory ammo and 4 different hand loads 168gr SMK, 180gr and 200gr Barnnes pills with VV n320. Everything tumbled with the 180gr being the best but still oblong slightly. Didn't have my chronograph with me but with the factory ammo having issues as well as the hand loads I'm kinda worried. Should be able to do some more loads this week to try and sort things out, any recommendations for bullet weight with a 1-7 twist? Also what OAL are people using I chose 2.200 as I wasn't sure where to start.

Thanks

[Maxduty]

I've shot the Remington UMC 220s with no keyholing shown. when I tried some handloads, they all keyholed. You can clearly see that the bullet hit the paper sideways. The holes looked like perfect silhouettes of the bullets. My loads were with Win 296 and Nosler 200 grain Accubonds. 8, 9 and 10 grains. I'm thinking I need more velocity to stabilize these loads. I don't think I'll be able to stay subsonic with them. Unfortunately, I don't have a chronograph, so I really have no idea how fast I'm pushing these loads currently. I may try increasing the neck tension a bit to see if they clean up, but I doubt they will.

I also have some IMR 4227 and picked up some Lil Gun to try out. we'll see how development goes.

[Red magnum]

Well I tried a couple more hand loads of 200gr Barnes tsx bullets but this time with 8.5 grains of Lil Gun. Still tumbling, gun shop has the rifle and will be contacting Remington about the issues.

I will update as I get more information.

[80hp]

....... I'm thinking I need more velocity to stabilize these loads. I don't think I'll be able to stay subsonic with them. Unfortunately, I don't have a chronograph, so I really have no idea how fast I'm pushing these loads currently.......

Old black powder shooters know that you load until the rifle makes a crack instead of a boom.
As you transition from subsonic to supersonic you will hear a noticeable change in the rifle's report.
If you load a couple of tenths of a grain less of powder than the transition point you should stay subsonic.

NOTE: The speed of sound varies with temperature and pressure.
Ignoring pressure, it is about 1160 fps at 100 deg F, to about 1070 fps at 20 deg F.
Most commercial subsonic ammo is loaded to about 1050 fps to cover all extremes.
If you live in the hotter parts of the country, you can load 50 or 75 fps faster than factory and still stay subsonic.
M.

[m4a1sof]

Update:

I finally got to take my rifle to not one but two gunsmiths, both said the crown, rifling twist rate, and dimensions all checked out. So, I decided to try some different ammo. All I had shot previously and what I experienced the keyholing with was the R300AAC8 Remington 220. I finally got my order in for the new L300AAC4 UMC 220 gr ammo and no keyholing. It functions better in my 8.5" AR15 as well. It seems to be loaded a little hotter than the R300AAC8, so that combined with the different shape bullet did the trick.

[tallburnedmidget]

Thanks for the update. Good to know that just trying some new ammo helped