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Sierra 125gr OTM bullets

Posted: Thu Dec 15, 2011 1:04 pm
by Burt
I can't seem to find any loading data for these bullets. Is it just an over-sight on my part or are these bullets not what I want for supersonic 300 BLK? I tried to push them in the case just to the bottom of the neck and the rib in the magazines push way to hard on the bullet IMO. ANY loading data would be a big help. I called Sierra and they had no data to give out at that time (about six days ago). I have H110, 296 and Lil'Gun.

Re: Sierra 125gr OTM bullets

Posted: Thu Dec 15, 2011 11:48 pm
by hoser
I would try data for the Nosler 125 gn ballistic tip. Use start data minus 5-10% or so.

I have a couple big boxes of them but have not had the time to do any load development.

Re: Sierra 125gr OTM bullets

Posted: Fri Dec 16, 2011 10:17 am
by Burt
Thanks Hoser. With the OTM bullet being so long I see no ther way to load it into the brass without pushing it pretty far in. Of course, not near as far as a 220gr bullet for sure. I measured the factory Remington (RM300AAC6) ammunition and the over all lengths were all over the place. Pricey ammo for that type of bad quality control, in my opinion. What do you think of the LiL'Gun powder for this cartridge? I like the idea of lower pressures and a little more velocity.

Re: Sierra 125gr OTM bullets

Posted: Sun Dec 18, 2011 4:46 pm
by Burt
The Remington Premier Match ammo measures 2.216"-2.242". I figure an over-all-length of 2.230" for my handloads should be good to go unless I need to be concerned with the magazine ribs hitting on the bullet sides. Doesn't seem to concern Remington so I guess it should be alright. This is new Remington brass and is all very close to 1.360" so I don't see any reason to trim even after resizing the neck (some are out of round). A load of 17gr to 18gr of LIL'GUN and WSR primers. Does this all sound okay? Some of you have had to have been there done that, any comments or information I should know?

Re: Sierra 125gr OTM bullets

Posted: Mon Dec 19, 2011 3:53 pm
by misterchaos
Here is my load recipe.
Bullet = Sierra 125 grain OTM
Powder = H110 - 18.4 grains (max load for me- some primers flattened)
Primer = CCI #400
Case = 5.56 LC 09 (300 blk specs once fired from Brad's warehouse)
OAL = 2.245 (mag length)
Light crimp (Lee FCD)

As always start 10-15% low and work up to this load. I take no responsibility for the safety of this load.

I don't have any chrono data but it functioned flawlessly and locked the bolt open on an empty magazine. At 50 yards using an Aimpoint micro I was able to shoot just around 1" 5 shot groups. Hope this helps.

Re: Sierra 125gr OTM bullets

Posted: Mon Dec 19, 2011 4:07 pm
by Burt
That helps a bunch, thank you!

Re: Sierra 125gr OTM bullets

Posted: Tue Dec 20, 2011 12:57 am
by JohnInNH
misterchaos wrote:Here is my load recipe.
Bullet = Sierra 125 grain OTM
Powder = H110 - 18.4 grains (max load for me- some primers flattened)
Primer = CCI #400
Case = 5.56 LC 09 (300 blk specs once fired from Brad's warehouse)
OAL = 2.245 (mag length)
Light crimp (Lee FCD)

As always start 10-15% low and work up to this load. I take no responsibility for the safety of this load.

I don't have any chrono data but it functioned flawlessly and locked the bolt open on an empty magazine. At 50 yards using an Aimpoint micro I was able to shoot just around 1" 5 shot groups. Hope this helps.

That's an OK load.. 19 gr is listed as max in my book and I can go to 20 w/o any noticeable pressure, but I get problems at 21. (with the Speer TNT which I usually can go a little over most other 125's )

The OTM,as you say, seats the base lower so that 18.4 gr load may be right on ..

Re: Sierra 125gr OTM bullets

Posted: Tue Dec 20, 2011 6:40 pm
by DaedalusX
misterchaos wrote:Here is my load recipe.
Bullet = Sierra 125 grain OTM
Powder = H110 - 18.4 grains (max load for me- some primers flattened)
Primer = CCI #400
Case = 5.56 LC 09 (300 blk specs once fired from Brad's warehouse)
OAL = 2.245 (mag length)
Light crimp (Lee FCD)

As always start 10-15% low and work up to this load. I take no responsibility for the safety of this load.

I don't have any chrono data but it functioned flawlessly and locked the bolt open on an empty magazine. At 50 yards using an Aimpoint micro I was able to shoot just around 1" 5 shot groups. Hope this helps.
I'd like to replicate that load with VV N110. Should I start at 16.5 or higher ?

Re: Sierra 125gr OTM bullets

Posted: Thu Dec 22, 2011 9:31 pm
by Sandsunsurf
misterchaos wrote:Here is my load recipe.
Bullet = Sierra 125 grain OTM
Powder = H110 - 18.4 grains (max load for me- some primers flattened)
Primer = CCI #400
Case = 5.56 LC 09 (300 blk specs once fired from Brad's warehouse)
OAL = 2.245 (mag length)
Light crimp (Lee FCD)

As always start 10-15% low and work up to this load. I take no responsibility for the safety of this load.

I don't have any chrono data but it functioned flawlessly and locked the bolt open on an empty magazine. At 50 yards using an Aimpoint micro I was able to shoot just around 1" 5 shot groups. Hope this helps.
My best load with the SMK 125 OTM was over 18.2 grains of H110, using AAC/Remington primed brass from Midway. CAOL 2.125, with a light crimp from a Lee FCD. I wasn't very impressed, not less than 2 MOA out of my 9" AAC upper.

Much better results with the much more expensive Barnes TTSX 130 gr boattail over 18.2 grains of H110, COAL 2.150.

Re: Sierra 125gr OTM bullets

Posted: Fri Dec 23, 2011 11:33 am
by Burt
I was wondering about the accuracy of these bullets. I guess one just has to load them up and see if all is well with the combination. I was looking at the load data at Hodgdon's site and see they have the 130gr bullets being listed with a higher powder charge than the 125gr bullets...a little odd.

My scales were acting up yesterday, took forever to get the powder weighed. I guess the scales are like me, old and only wants to work at certain times. Thanks for all the info!

JohnInNH, where did you find the max charge of 19gr (H110?) for the TNT 125gr?