N105 load workup

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Demphna2
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N105 load workup

Post by Demphna2 » Sat Jul 23, 2022 10:43 am

I've read just a few posts through the thousands of pages I've been reading about working up a load with N105.

Is it recommended to start low and go up with this powder as opposed to the standard operating procedure with subsonic load development in general?

Going to start at 7 gr if this is the case.

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dellet
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Re: N105 load workup

Post by dellet » Sat Jul 23, 2022 10:48 pm

It will depend on bullet weight and barrel length.

For 190-210 grain bullets around 8 grains is 1000 fps in an 8” barrel. Changing seating depth can vary speed and cycling ablility for fine tuning.
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Re: N105 load workup

Post by Demphna2 » Sun Jul 24, 2022 1:31 am

dellet wrote:
Sat Jul 23, 2022 10:48 pm
It will depend on bullet weight and barrel length.

For 190-210 grain bullets around 8 grains is 1000 fps in an 8” barrel. Changing seating depth can vary speed and cycling ablility for fine tuning.
190 gr Sub -X in a 6.5" barrel. V seven uses a slightly shorter gas tube length than pistol. Starting at 2.09 overall length.

Dellet,
Reading the massive amounts of posts you have encouraged me to give N105 a try.

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Re: N105 load workup

Post by Demphna2 » Sat Aug 06, 2022 12:16 pm

N105
190 gr Sub-X
COL 2.09
With Ultra 9 suppressor
8 gr - 1076, 1082. Cycled, No BHO
7.5 gr - 1021, 1020. Cycled, No BHO
7 gr - 949, 953. Cycled, No BHO
6.5 gr - 881. Cycled, No BHO

Tried last 4 shots with titanium BCG, no BHO

I'm thinking I'll seat longer and add powder to tweak velocity. Does that sound like a good plan or should I try anything else first?

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dellet
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Re: N105 load workup

Post by dellet » Sun Aug 07, 2022 11:15 am

What I normally do is find a charge weight that will cycle, then adjust velocity with seating depth.

I would probably keep 8 grains and move the bullet out to around 2.15”. Then based on velocity, add powder if needed. It’s imortant to keep good records of changes.

Your 8 grain load is borderline in velocity, you don’t really want to go any faster. Moving the bullet out will reduce velocity, and increase gas pressure where you need it, at the muzzle.

Make sure if your upper has less than 200 rounds through it, to have it very well oiled.

I would be interested to know the size of the gas port in your barrel. The shorter the tube the smaller the port will be. To keep from hyper cycling supers, it will need to be very small. That will work against the faster powders for subs.

For what it’s worth for 190’s of various bullets I use 7.9-8.2 grains
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Re: N105 load workup

Post by Demphna2 » Sun Aug 07, 2022 1:56 pm

dellet wrote:
Sun Aug 07, 2022 11:15 am
What I normally do is find a charge weight that will cycle, then adjust velocity with seating depth.

I would be interested to know the size of the gas port in your barrel. The shorter the tube the smaller the port will be. To keep from hyper cycling supers, it will need to be very small. That will work against the faster powders for subs.

For what it’s worth for 190’s of various bullets I use 7.9-8.2 grains
Hey Dellet, thank you for the suggestions. From what I understand, this V7 barrel uses a .105 gas port, but they use a proprietary gas tube length that is shorter than pistol.

I used slow motion to watch how far back the BCG was going when shooting 8 gr. It went about 2/3 of the way back. I am using a maxim brace with the JP SCS XS standard. Out of curiosity, and because I like to tinker, I'm wondering if I were to swap out the tungsten weight for another steel weight and use their lightest spring to get it to hold the bolt open on last round.

I have 2 of these XS SCS so swapping one out would be fairly easy. Any thoughts on this?

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Re: N105 load workup

Post by Demphna2 » Sun Aug 14, 2022 6:18 pm

Loaded up 7.8 gr, 8 gr, 8.2 gr, and 8.4 gr. None of them had BHO. But they were close.

7.8 - 1025
8 - 1060
8.2 - 1088
8.4 - 1110

Going to try a lighter spring and possibly a steel weight to replace the tungsten one on the standard JP SCS XS. Which brings up the question. Is it best to just try the steel weight and lighter spring first?

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Re: N105 load workup

Post by dellet » Mon Aug 15, 2022 12:48 pm

Demphna2 wrote:
Sun Aug 14, 2022 6:18 pm
Loaded up 7.8 gr, 8 gr, 8.2 gr, and 8.4 gr. None of them had BHO. But they were close.

7.8 - 1025
8 - 1060
8.2 - 1088
8.4 - 1110

Going to try a lighter spring and possibly a steel weight to replace the tungsten one on the standard JP SCS XS. Which brings up the question. Is it best to just try the steel weight and lighter spring first?
That’s why I keep a standard spring, and both a carbine. 2.7 oz and an H2 buffer around. Trouble shoot with the parts it was designed to work with. Then modify.
300 Blackout, not just for sub-sonics.

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Re: N105 load workup

Post by Demphna2 » Mon Aug 15, 2022 5:00 pm

dellet wrote:
Mon Aug 15, 2022 12:48 pm
Demphna2 wrote:
Sun Aug 14, 2022 6:18 pm
Loaded up 7.8 gr, 8 gr, 8.2 gr, and 8.4 gr. None of them had BHO. But they were close.

7.8 - 1025
8 - 1060
8.2 - 1088
8.4 - 1110

Going to try a lighter spring and possibly a steel weight to replace the tungsten one on the standard JP SCS XS. Which brings up the question. Is it best to just try the steel weight and lighter spring first?
That’s why I keep a standard spring, and both a carbine. 2.7 oz and an H2 buffer around. Trouble shoot with the parts it was designed to work with. Then modify.
The brace I'm using uses smaller components than normal. The JP SCS XS is another option they offer. I could go with their version of buffers and springs. I think the JP SCS XS standard weight buffer is 2.2 oz. If I drop the buffer weight to 2 steel weights, that gives a buffer weight of 1.4 oz.

My thought is to try a lighter spring first though. Kind of concerned none of this is going to get it to work, but there's only one way to find out

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dellet
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Re: N105 load workup

Post by dellet » Mon Aug 15, 2022 5:43 pm

Demphna2 wrote:
Mon Aug 15, 2022 5:00 pm
dellet wrote:
Mon Aug 15, 2022 12:48 pm
Demphna2 wrote:
Sun Aug 14, 2022 6:18 pm
Loaded up 7.8 gr, 8 gr, 8.2 gr, and 8.4 gr. None of them had BHO. But they were close.

7.8 - 1025
8 - 1060
8.2 - 1088
8.4 - 1110

Going to try a lighter spring and possibly a steel weight to replace the tungsten one on the standard JP SCS XS. Which brings up the question. Is it best to just try the steel weight and lighter spring first?
That’s why I keep a standard spring, and both a carbine. 2.7 oz and an H2 buffer around. Trouble shoot with the parts it was designed to work with. Then modify.
The brace I'm using uses smaller components than normal. The JP SCS XS is another option they offer. I could go with their version of buffers and springs. I think the JP SCS XS standard weight buffer is 2.2 oz. If I drop the buffer weight to 2 steel weights, that gives a buffer weight of 1.4 oz.

My thought is to try a lighter spring first though. Kind of concerned none of this is going to get it to work, but there's only one way to find out
Sorry, but can’t really help. I know the system and load data quite well for the system as designed. Go help, I really would need to know how you designed your system to operate. In essence you have redesigned the AR15 into something it was never purposed to do.

You also want to use load data that was never really developed to work commercially because it has a narrow window of operating pressures.

Combining to experimental systems is problematic. Make sure one works properly. Then the other. Then combine. There’s no easy way about it.
300 Blackout, not just for sub-sonics.

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