Doing My Very First Reload w/ Sierra 125gr OTM-Advise Please

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StorminNormin
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Doing My Very First Reload w/ Sierra 125gr OTM-Advise Please

Post by StorminNormin » Sun Apr 21, 2013 12:52 am

I am completely new to reloading and decided to reload once I got into the 300 BLK. While buying equipment for reloading the only bullets I could find at first were the Sierra 125gr OTM and now I see there is no loading data on any of the powder website for this bullet which seems strange. Of course now I have obtained bullets that have reloading data all over the place for them but I figured I would start with the Sierra 125 OTM for a plinking round. I have searched all over the forum and find people using different loads and different COAL. My main question is to the COAL and what is recommended or is it OK for it to vary a little as long as it stays within a range and does that COAL depend on the powder?

I am going to use Hodgdon Lil'Gun and so far I have read that OAL with this bullet is good at 2.230, but not to be longer than 2.245. I see people going with 2.245, 2.083, 2.194, 2.230 and read in one post that someone called Sierra and said they recommended the OAL to be 2.210 and to use a starting load of 15.7gr of Lil'Gun.

I will be shooting a Noveske 10" 300 BLK.
Sierra 125gr OTM 2121c
Lake City once fired brass that I cut down and formed to be 1.358 - 1.360.
CCI400 Primer
I plan to start with 15.7gr of Lil'Gun and work it up in .3gr intervals; I have loaded 10 rounds each so far of 15.7gr, 16gr, and 16.3gr.
I am going with 2.230 COAL, but even though I have the seating die tightened down I have had a COAL range from 2.230 - 2.233.
I am using a Redding 2 die set and putting a light 1/2 turn crimp with a Lee FCD.
I am loading on a Dillon RL550B progressive although I am pouring the powder manually right now as I work up the loads.

Sorry if I am asking stupid questions and I hope I am providing detailed enough information for some good feedback from people with experience. Am I on the right track here or should my COAL be different and do you have any other recommendations on any thing I should do different? Since this is my very first load to do I have tried to learn as much as I can before getting started and just want to share what I am doing before I actually go shoot my first reloads.

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StorminNormin
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Re: Doing My Very First Reload w/ Sierra 125gr OTM-Advise Pl

Post by StorminNormin » Sun Apr 21, 2013 5:39 pm

Well I decided to change my OAL to 2.210 since when I did some more reading that would put the ogive of the bullet at the rib in the magazine. Today I went and tested 5 worked up loads and need to work up some more until I find the right fit for me as there were no signs of pressure at the top load I tested today.

Noveske 300BLK
Pistol length gas system
10", 1:7
MagPul PMAG, 30RD
125 gr Sierra OTM
Hodgdon Lil'Gun 15.7gr, 16.0gr, 16.3gr, 16.6gr, 16.9gr
LC 5.56, reformed to 300BLK
CCI 400 Small Rifle
2.210" OAL
1/2 turn light crimp Lee FCD
No Chrono yet
Zero Issues on any of the loads. All feed, fire, and eject fine.
Bolt held open on last round.
I fired 5 rounds suppressed and 5 rounds unsuppressed for each load.
My suppressor is the AAC 762-SDN-6 and with factory ammo there is not much of a shift in POI with the suppressor on or off but I did have POI with each load today.

All shots fired at an indoor range at 50 yards
Image

This is how it will shoot at 50 yards with factory Remington 115gr 300 BLK
Image

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Jargonhead
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Re: Doing My Very First Reload w/ Sierra 125gr OTM-Advise Pl

Post by Jargonhead » Sun Apr 21, 2013 8:32 pm

1. Welcome to reloading.
2. Go buy a chrony.
3. Way too light a load.
4. Read Maryland_Shooter's thread on Lil' Gun. Best info out there.

Rob
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StorminNormin
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Re: Doing My Very First Reload w/ Sierra 125gr OTM-Advise Pl

Post by StorminNormin » Sun Apr 21, 2013 8:37 pm

Will do. A chrony is the next item on my list. I knew I was starting very low but being new to reloading I wanted to play it safe and I will continue to work up. I will definitely read that as I am trying to learn as much as I can.

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Re: Doing My Very First Reload w/ Sierra 125gr OTM-Advise Pl

Post by buffalocountry » Sun Apr 21, 2013 9:31 pm

Yor are locked on, get all the books from Speer, Nosler, Hodgdon and let them be your bible. A chronograph will help you get an idea of the chamber pressure you are working up to. Hodgdon shows a max load of Lil Gun 18.0 @ 2185 fps with 40.800 CUP and when you get close to a max load use small increments in your powder increase of tenths of a grain. Safety first. I just ordered a trimmer from http://www.littlecrowgunworks.com/ that goes into a drill and it bottoms out when the shoulder touches. They indicated it only varies a thousandth of an inch. $69.95 + shipping. Hope it speeds up my brass forming set up. Check out this web site as they are going to start making some 300 ammo but a draw back is you have to put 50% down to hold your spot in line. Not cheap either but who is anymore. One fellow indicated he was waiting on Black Hills for some but I guess it may have a waiting time of 12 months or so. Call them for a list of ammo and prices @ (605)791-1974 Ask for Kathy Greenhaw. Website http://www.captechintl.com/ Hope you find this useful...

20X11
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Re: Doing My Very First Reload w/ Sierra 125gr OTM-Advise Pl

Post by 20X11 » Mon Apr 22, 2013 7:55 pm

As I recall Mr. Silvers worked with Sierra on that bullet design (2121c) and on another thread in this forum indicated it was designed to be loaded at an OAL of 2.20". I'm sure he will jump in if I have mis-represented his post.

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StorminNormin
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Re: Doing My Very First Reload w/ Sierra 125gr OTM-Advise Pl

Post by StorminNormin » Mon Apr 22, 2013 9:45 pm

20X11 wrote:As I recall Mr. Silvers worked with Sierra on that bullet design (2121c) and on another thread in this forum indicated it was designed to be loaded at an OAL of 2.20". I'm sure he will jump in if I have mis-represented his post.
I ended up going for 2.210" which is very close and I am sure it was for the same reasons I did but I would love to hear his input!

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StorminNormin
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Re: Doing My Very First Reload w/ Sierra 125gr OTM-Advise Pl

Post by StorminNormin » Mon Apr 22, 2013 10:01 pm

buffalocountry wrote:I just ordered a trimmer from http://www.littlecrowgunworks.com/ that goes into a drill and it bottoms out when the shoulder touches. They indicated it only varies a thousandth of an inch. $69.95 + shipping. Hope it speeds up my brass forming set up.
I have the Little Crow Gun Works and it works PERFECT! I use it in a drill press and just raise the brass up into it to trim it properly. I think that is easier than having to hold a drill in one hand and the case in the other. I highly recommend it.

I chop the neck off the 5.56 brass first, then chamfer and deburr, then put it in the sizing die, and then trim it to proper legnth in the Little Crow Trimmer.

20X11
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Re: Doing My Very First Reload w/ Sierra 125gr OTM-Advise Pl

Post by 20X11 » Mon Apr 22, 2013 11:40 pm

StorminNormin wrote:
20X11 wrote:As I recall Mr. Silvers worked with Sierra on that bullet design (2121c) and on another thread in this forum indicated it was designed to be loaded at an OAL of 2.20". I'm sure he will jump in if I have mis-represented his post.
I ended up going for 2.210" which is very close and I am sure it was for the same reasons I did but I would love to hear his input!
Whoops...I had it wrong...No shorter than 2.230 and no longer than 2.245....see the following thread...scroll down to 300BLKs post.

viewtopic.php?f=141&t=78581&hilit=Sierra+125

Also interesting...
viewtopic.php?f=141&t=78419&hilit=Sierra+125

ToyotaGuru
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Re: Doing My Very First Reload w/ Sierra 125gr OTM-Advise Pl

Post by ToyotaGuru » Tue Apr 23, 2013 3:21 pm

I went out to the Sierra factory to day to pick up some factory seconds and talked to one of the ballistics techs while I was there. They had a copy of the new 300 blackout data to go into the new book, but would not release a copy yet, but did write some down for me.
Here is what I got

Sierra 125 gr match king #2121
OAL 2.210"
H4227 16.2-18.7gr
most accurate load at 18.7gr
LilGun 15.7-17.2gr
most accurate load at 17.2gr

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