300 Whisper reloading issues and questions

[ahoss79]

I have a 10.5" barrel that I got from TC555 and have just completed the upper. Now I am running into some issues with the reloading.

I am using .223 casings and really haven't had an issue with making the brass. They fit in the case guage easily and have minor resistance going into the chamber.

I loaded up some 240gr Sierra HPBT bullets with 12.5gr of Reloader 7 and set them at an overall length of 2.26 based off the Sierra reloading manual. They wouldn't fit in the case guage or the chamber. After forcing it into the chamber an forcing it back out, I could see where the bullet was making contact. I did a search on here and found where someone mentioned that2.13 overall length was probably the max. So I set a bullet at 2.13 and seemed to notice a little more resistance than normal when setting it that far in. Will not fit into the case guage or the chamber.

Is it possible that the bullet has compressed the powder enought to expand the casing? Has anyone experience this before or heard of it?

Also, what would you all recommend for bullet, powder and speed for a break in load? I did a search and couldn't find anything on break in loads.

Appreciate any tips you all could give me.

[TCCrewchief76]

Get a bump gauge and find out what your Jam length on your bullets are. With the right tools, there's no reason to be guessing. Welcome to the club!

[ahoss79]

I went ahead and markered up half of a loaded bullet that is at 2.13 overall length and forced it in. After pulling it out you can see whete the casing, not the bullet is making contact. Measuring with calipers the casing at one point is .02 wider. I've never run into this issue before, but I guess that I will be limited to smaller amounts of powder with Reloader 7 unless I use smaller bullets.

Does anyone else have much experience with Reloader 7 using it in an AR setup?

[TCCrewchief76]

RL-7 seems a bit slow for the pistol position gas port AR's. I'd try the 2400/Enforcer burn rate area.

:welcome: Kevin

[rsilvers]

RL-7 seems a bit slow for the pistol position gas port AR's. I'd try the 2400/Enforcer burn rate area.

:welcome: Kevin

Depends on the gas port size. The problem I have with RE-7 is that I sometimes run out of case capacity.

[snipecatcher]

If its a TP555 barrel with his selectable gas block, 2400 will give you plenty of gas for reliable cycling. You should be around 8-9 grains. VVN110 works well too. The 240s take up a lot of case capacity, which is what makes them ideal for subsonic shooting, but above 9 or 10 grains of powder, you run out of capacity, depending on seating depth of course.

[Hoser]

I would try a different powder.

[ahoss79]

Depends on the gas port size. The problem I have with RE-7 is that I sometimes run out of case capacity.

That is exactly what I am running into. Makes me feel better just knowing someone else has experienced this. I went ahead and picked up some 2400 and loaded some 150gr SP's for break in with 14.8gr of powder. Hopefully I'll get to shoot it this weekend.

I appreciate the feedback. I've spent quite a bit of time trying to figure out what I was doing wrong, pulling bullets, resizing casings, etc. I guess thats how you learn.