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3N38 in 38 SC. Weird chrono results


dvc4you

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So I finally got my hands into some VW 3N38 to try in my Akai, using 124 gr MG JHP.

I loaded 2 test batches: 10.0 gr and 10.3 gr.....and I got the same results !!????

Loads were weighted thoroughly in a Dillom electronic scale averaging 5 throws before loading the batch.

Here are the results:

10.0gr

1394

1374

1381

1375

1371

1378

1380

1380

AVG 1379 PF = 171 STD = 6

10.3gr

1397

1374

1363

1378

1378

1377

1374

AVG 1376 PF = 171

Used Prochrono Digital with infrared led screens in an indoor range.

Here is the top of the gun:

Should I try 10.5gr?

post-3555-0-01750700-1442432425_thumb.jp

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What was your oal? I flatten primers at 10.5 under a 115g. If the guns flat and a 171 at 10.g I would leave it alone. With the whole you might not be getting a complete Bernat 10.3 there for the extra powder isn't doing anything to add velocity.

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Ya. Only thing I can think of is holes... I have a svi w 4 holes I haven't had a chance to chrono yet. Hybrid barrels loose gas quick. W less barrel lenth to act on it 10g may be all the time you have to burn? Is your gun flat at 10g?

Frankly this gun has always shot very flat, I only shot 40 rounds and I liked the feel, I am just trying to get to the ideal load and stick with it. I am not an experienced open shooter. I just know I like how 3N38 (10.0 gr.) feels compared to 9.3 gr of HS6. I think it is flatter. It also "feels" better than 11.3gr of N105 which I shot in the same session and produced a PF of 172. Just experimenting....
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So have I, I think you might have plateaued

This happened to me with the same powder 8.2 grams and 8.4 grains yielded the exact same, in fact I actually dropped 2 points in PF

Same powder 3n38

Edited by Open1215
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Will try 10.5 gr to confirm the trend, if PF remains at 171 will use 10.0 gr. in a couple of matches to see how it feels.

You might even try a little less than 10 grains and see if you get the same velocity. With so many holes and how slow 3n38 is, you're only going to get so much burn... I'd wager 9.8 will get you something very close to the same PF.

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Will try 10.5 gr to confirm the trend, if PF remains at 171 will use 10.0 gr. in a couple of matches to see how it feels.

You might even try a little less than 10 grains and see if you get the same velocity. With so many holes and how slow 3n38 is, you're only going to get so much burn... I'd wager 9.8 will get you something very close to the same PF.
Thanks that is a good idea.
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I have a STI GM and a Ganns STI in 38SC. The STI GM has three popples. The Ganns STI has 4 popples but they are smaller in diameter than the one ones on the STI GM.

I am loading to 1.235, small rifle primers, 124 gr Precision Delta FMJ projectiles and 10 gr of 3n38.

The STI GM averages 1422 fps with a PF of 176.3 SD is 7. The Ganns STI averages 1428 fps for a PF of 177.1 SD is 9

I could easily make major at 9.5 grains of 3N38 but the dot behaves so much better at 10 grains. At 9.5 gr of powder, the STI GM averages 1383 PF 171.5 SD 8 and the Ganns STI averages 1396 PF 173.1 SD 8.

The weather conditions that day (8/11/15) were 82 F, RH of 71%, elevation 656 feet.

If you are going to be at the Statesville CSOS match this Sunday, you are welcomed to use my chronograph as a friend wants to chrono some rounds after the match. I use a Pro-Chrono as well.

Edited by JMike
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I have a STI GM and a Ganns STI in 38SC. The STI GM has three popples. The Ganns STI has 4 popples but they are smaller in diameter than the one ones on the STI GM.

I am loading to 1.235, small rifle primers, 124 gr Precision Delta FMJ projectiles and 10 gr of 3n38.

The STI GM averages 1422 fps with a PF of 176.3 SD is 7. The Ganns STI averages 1428 fps for a PF of 177.1 SD is 9

I could easily make major at 9.5 grains of 3N38 but the dot behaves so much better at 10 grains. At 9.5 gr of powder, the STI GM averages 1383 PF 171.5 SD 8 and the Ganns STI averages 1396 PF 173.1 SD 8.

The weather conditions that day (8/11/15) were 82 F, RH of 71%, elevation 656 feet.

If you are going to be at the Statesville CSOS match this Sunday, you are welcomed to use my chronograph as a friend wants to chrono some rounds after the match. I use a Pro-Chrono as well.

Thanks for the offer. I will be there.

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Yes, it seems very odd, I was using 11.6gr of N105 and is highly compressed but 11.6 gr gave me more fps than 11.3gr. Why would this not be the case with 3N38? Will reconfirm this Sunday with another chronograph. I have loaded 10.5 and 9.8gr, will report back as how they behave.

Edited by dvc4you
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So we chronographed yesterday and here are the results:

38Supercomp VW 3N38 MG 124gr JHP WSRP OAL 1.235

Charge AVG STD PF

9.8gr 1325 11 164.3

10.5gr 1396 12 173.1

So it seems that the 10.3gr charge that I chrono last week was a mistake.

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