Sierra 125 gr OTM

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USBP379
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Re: Sierra 125 gr OTM

Post by USBP379 »

ipittythefoo wrote:Are the Sierra 125 gr OTM the same as the 125 GR Spitzer? If not what's a good over all length for the Sierra 125 gr Pro-hunter?
Per data I've got from Western Powders, I seat Pro-Hunters to 2.035" and have had good results with this.
Zed Stewart
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Location: Cuero, Texas

Re: Sierra 125 gr OTM

Post by Zed Stewart »

Cotys wrote:The Hodgdon web site lists several 300 BLK loads including the Sierra 125. I loaded 50 and shot them this past weekend. I spent most of my time with 220 grain Sierra loads. Hodgdon recommends COL of 2.050 for the 125 Nosler.

Leupold recommends sighting in at 50 yards with the 220 grainers and then you should be close at 200 yards. I only had 150 yards to shoot, but was on paper. It looked like I might be a little low at 200 but it will take some trigger time to be sure. All function well with a Gemtech NVT suppressor.

One surprising thing for me, out of an 8" Noveske, all the loads were faster than advertised. I've read that may be due to lack of friction in a short barrel.

Image

My load was:

17.5 Lil' Gun
125 Sierra BT
Remington 7 1/2 primers
LC brass from Brad's
COL 2.050

Chronograph
Average 2239 with 17.5 Lil’ Gun

http://data.hodgdon.com/cartridge_load.asp
Are these numbers for the 8" Novske barrel you mentioned?
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Cotys
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Re: Sierra 125 gr OTM

Post by Cotys »

Zed Stewart wrote:
Cotys wrote:The Hodgdon web site lists several 300 BLK loads including the Sierra 125. I loaded 50 and shot them this past weekend. I spent most of my time with 220 grain Sierra loads. Hodgdon recommends COL of 2.050 for the 125 Nosler.

Leupold recommends sighting in at 50 yards with the 220 grainers and then you should be close at 200 yards. I only had 150 yards to shoot, but was on paper. It looked like I might be a little low at 200 but it will take some trigger time to be sure. All function well with a Gemtech NVT suppressor.

One surprising thing for me, out of an 8" Noveske, all the loads were faster than advertised. I've read that may be due to lack of friction in a short barrel.

Image

My load was:

17.5 Lil' Gun
125 Sierra BT
Remington 7 1/2 primers
LC brass from Brad's
COL 2.050

Chronograph
Average 2239 with 17.5 Lil’ Gun

http://data.hodgdon.com/cartridge_load.asp
Are these numbers for the 8" Novske barrel you mentioned?
Yes, an 8" Noveske, with a suppressor.
Joelogic
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Re: Sierra 125 gr OTM

Post by Joelogic »

Has anyone gotten these up to 2250fps with A1680 or H110 out of a 16" barrel? I am trying to make a 280pf. I only loaded my test rounds up to 20.5gr of A1680 and was barely hitting 2000fps.

I can make power factor with regular 150gr fmj bullets but I really like these sierra bullets.
bjkrauel
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Re: Sierra 125 gr OTM

Post by bjkrauel »

I have found I have the same results with this particular bullet where the greater amount of powder begins decreasing the accuracy, at least with my loads. But other than that I am impressed with this round.

My rds are being shot out of a noveske 8 inch barrel as well.

Loads:
125 gr. Otm
Winchester .223 brass cut down and sized.
Winchester small rifle primers
16.8gr of W296
OAL 2.230"
5 rd grps averaging 3/4" at 50 yds.
(bump that up to 17.5 grains and group increased to 2")


125 gr nosler BT
16.7 gr of W296
OAL 2.060"
1/2" 5 rd group avg. at 50 yds.

No malfunctions with 120 plus rds fired.

Love this round!
Pete43
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Re: Sierra 125 gr OTM

Post by Pete43 »

Hi guys, i'm new here so I may may a mistake every now and then. I may not be very organized.

I've got a model 1 300 blkout upper on a double star lower. I have a 7.62x39 upper that won't cycle the bolt using subs. So I got the 300 last week.
I've been shooting 30 yrds (about as far as i can see:-)with groups of about an inch with an eotech 517. I'm trying the 125gr #2121's from Midway and the 220 smk's and the 220 Hornady RN.

125gr SMK 17.3g h110 1955fps
18.1gr=2123fps had OAL=2.200 (touched powder@ 2.100)
hit lands at 2.225 OAL cycles fine.

Hornady 220gr rn 11.1 A1680 OAL=2.080 fps=1135 nocycle (almost)
220gr round nose 11.5g imr4198=1040fps
can't use Pmag with 220 bn.

220 SMK 11.1 A1680 OAL=2.120 fps=1060 cycles and locks the bolt on last shot.
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Cotys
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Re: Sierra 125 gr OTM

Post by Cotys »

From reading various forums, I've seen that the Hornady Rn are only good for bolt guns. They don't cycle in an auto. I had bought a box of them, its all my local retailer had in 220 grain. I hadn't opened them and took them back after reading. So I just ordered more 220 SMKs.

My 220 SMKs were a little faster, I have a set of step down loads from 11 to 10.5 grains 1680 to go try today.
Pete43
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Joined: Tue Feb 21, 2012 4:20 pm

Re: Sierra 125 gr OTM

Post by Pete43 »

I just shot 6 more subs. 3 bn and 3 smk with 10.6gr A1680
(Hornady 220 ball nose)
1st-984fps 2nd-1035fps 3rd-1017fps
And at 90 yards i thought their 1.5" group wasn't too bad. Oh and they cycled fine in a cheap AR stoner mag. OAL was 2.080
I kinda like the ball nose. I'm hoping they will mushroom at least a little.

Shot 3 220g SMKs with the same 10.6gr A1680 They opened up to about a 3" group. (it could be me)
1st-946fps 2nd-1005fps 3rd-1022fps OAL=2.120

I'm on the 6 month waiting list for a yhm 7.62qd SS can. I think these fps will be ok
nvshooter
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Location: Sparks NV

Re: Sierra 125 gr OTM

Post by nvshooter »

Finally got a chance to get some rounds over the chrono. I shot 5 5 shot strings it was 60degres. Shot out of the 8" Noveske with 17 gr lil gun. After averaging all the numbers here's what got

1893fps
ES 105
SD 44

I was surprised the ES and SD was so high cause it's a pretty accurate load. All in all I'm very happy I was told by 300blk I should expect about 1911fps with this bullet out of a 8" barrel and my load is a lil light so it seems like I'm right where in should be.
Rick Finsta
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Location: Wisconsin

Re: Sierra 125 gr OTM

Post by Rick Finsta »

Sorry for the necropost, but this was the best collection of 125gr data I've found that included 8" SBRs.

I started working up my load using Sierra and Hogdon's load data, and my 17.0gr of H110 with a 2.110 COAL and Magtech 7 1/2 primers piecerd a primer (my firing pin was eroded due to gas cutting the last time this happened with a M193 factory load, so I was expecting to start seeing it happen - swapped it out and all is fine). I got around 1920fps and was concerned that was high based on what other bullets seem to lose per inch of barrel length. My primers were not flattened, ejection was almost anemic compared to what I am used to (overgassed 5.56 in a 14.5" suppressed midlength), and I had no ejector wipes or other signs of poor timing or too hot of a load. I have some 17.5gr loads already put together; but my question is this:

With a Noveske 8.2" barrel and a supressor, what should I be seeing for velocity with a safe load for the 125 SMK #2121 and H110 powder?
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