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To low velocity from a new SVI Sighttracker .40?


Cardinal

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I finally got my new CED M2 chrono with IR screens and the chance to check and work up my .40 loads.

But I got lower velocities than I expected.

My last couple of loads:

Both using Fiocchi cases, Partizan 180gr TMJ bullets, OAL 1.17", Federal SR primers

6.3gr N340 gave 959fps (average of two 10 round strings)

5.6gr N320 gave 926fps (same)

I of course understand that each barrel is different and two similar guns can have very different muzzle velocity. But by looking at data from here and on IPSC GV I expected more.

The 320 load should be clocking over 1000 based on other results.

The thing that would make the most sense to me, would be if the scale (Hornady scale) is showing one grain to much and the loads are in reality 5.3 and 4.6gr...

But I weighed some bullets and it seems correct. Will be getting a Electronic scale at the end of next week so I'll check then.

Or the chronograph is screwed up.

Any one have any other suggestions or solutions in the meantime? Or have similar experiences?

Edited by Cardinal
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That does seem to be a bit low. I'm running under 5gr of N320 at 1.195 and 180gr Zeros in Starline cases and getting an easy 171pf out of an Edge.

I too had a load with N320 at 1.196.

5.3gr 320 gave only 811 fps.

So I decided to try some shorter rounds.

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I would also try different bullets with the same loads to see what the variation frm bullet to bullet was. It could be that the barrel doesnt like the Privi bullet as it may not engage as good as a zero or Montana. Not knocking the bullet just the gun may like the others better. I know my sighttracker doesnt like the 200 gr rainier, but does fine with the 180 rainier, zero or montana. It also doesnt seem to like the masterblasters as wellas good ole lead bullets of about any weight.

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I would also try different bullets with the same loads to see what the variation frm bullet to bullet was. It could be that the barrel doesnt like the Privi bullet as it may not engage as good as a zero or Montana. Not knocking the bullet just the gun may like the others better. I know my sighttracker doesnt like the 200 gr rainier, but does fine with the 180 rainier, zero or montana. It also doesnt seem to like the masterblasters as wellas good ole lead bullets of about any weight.

Good idea.

Will try some other bullets.

But I hope thats not the case as Zero/Montana isn't available here and about the only economical choice is partizan ($105/1k) and Frontier ($85/1k)

Example. Hornady HAPs are about $320/1k! (thanks to an exceptional greedy local brach of Midway USA)

But will try to find some other bullets.

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Indoors.

Wont get the chance to chrono outdoors for three to six weeks.

around 8-9 feet I guess.

Can also experiment more with longer distances as well

If you are indoors are there florescent lights on in the range? These can cause incorrect readings even when using the IR skyscreens.

MDA

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If you are indoors are there florescent lights on in the range? These can cause incorrect readings even when using the IR skyscreens.

MDA

Yes.

Forgot to mention, I also chrono'ed Blazer Brass 9mm 115gr from my S&W M&P. They clocked 1113.4fps and thats close to factory specs (1145fps)

So I get the impression the chronograph is ok.

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If the gun has an AET barrel the lower velocity is normal. The AET barrels are much slower than other ones. I have a load that shoots 175 PF out of my friends non AET sight trakker but shoots 167 out of my two and another friends gun that do have AET barrels. I just have to load them a bit hotter to make sure I make major.

Brian

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If the gun has an AET barrel the lower velocity is normal. The AET barrels are much slower than other ones. I have a load that shoots 175 PF out of my friends non AET sight trakker but shoots 167 out of my two and another friends gun that do have AET barrels. I just have to load them a bit hotter to make sure I make major.

Brian

The specs listed by the distributor states its a non-aet barrel.

When the gun arrived I looked at the Barrel Accuracy Certificate included. The Certificated stated the barrel was a AET and the serial no. matched. So I contacted SVI to check with them. Brandon Strayer answered quickly. He stated AET barrels are marked "AET" on top and mine doesn't have that. So he said I had a Non-AET. BUT he also said that normally ONLY AET barrels comes with a certificate and couldn't really explain why I had one with my gun...

I guess in theory it could be a AET barrel and they simply forgot to mark it as such.

Edit: Also thanks for all the suggestions so far.

Edited by Cardinal
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My experience has proven to be the same.

My wife and I shoot SV's and mine has the AET barrel. I load 4.9 to 5.0 of titegroup for a 180 grain bullet and make about a 170 PF with either MG or Zero bullets. On the other hand the wife has to load dwon 4.6 to 4.7 with the same components or she is running at 175 plus power factor. She has a Schuemann barrel in her pistol. OAL is 1.175

Hope this helps.

Jon

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I have two Sight Trackers, both with AET barrels. In both guns this load makes 171 PF. 5.0 gr N-320, 180gr Zero JHP, Winchester SRP loaded to 1.175 OAL. I just measured the OAL again because I took my loader apart before I loaded the last rounds I chronoed.

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This is an interesting discussion that leads me to believe that I need to keep my SV w/ AET forever. I get higher velocities than the one or two other guns I've chronoed my load through. I know it's not a lot of data, but I always assumed the AET was a faster barrel. This is the TiN ceramic coated AET with Masterblaster bullets. 167 PF with 4.4 grains of comp (similar performance to N320 I'm told).

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I talked to the SVI distributor, and in their experience the latest SVI barrels have been a little slower and they have had to increase their loads by 0.2-0.3gr to maintain the velocity.

Went to the range today and the N320 load listed in the first post chrono'ed 970fps/175PF today...

6.5gr N340 averaged 1002fps.

But when I cleaned the gun yesterday, I noticed a LOT of copper in the barrel. It looked like I fired several hundred Barnes X thru it and not 100-200 FMJ...

Shot 70 rounds today and there is some build up.

Will try some other bullets when I get a hold of some.

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I also noticed that the barrels were slower when the pistols are new.

My two SVs were slower than my STI until I shot around 1500 to 2000 rounds with each.

Then I regain the few Fps needed to achieve the right PF.

We experienced this on 5 different pistols and the phenomenom was identical.

My two pistols were also ordered as non AET barreled but I got the certificate. And they are clearly not AET barrels (no fluting in chamber).

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I also noticed that the barrels were slower when the pistols are new.

My two SVs were slower than my STI until I shot around 1500 to 2000 rounds with each.

Then I regain the few Fps needed to achieve the right PF.

We experienced this on 5 different pistols and the phenomenom was identical.

My two pistols were also ordered as non AET barreled but I got the certificate. And they are clearly not AET barrels (no fluting in chamber).

Thx.

I've shot around 1k so far. I'll see how it progresses.

Did you have any problems with copper buildup in the barrel?

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I don't have the answer but i do have a story.

I have and SVI with a Schuemann Ultimatch barrel. Not sure of the exact round count but around 6k throug it. i noticed some copper build up so i decided to clean it just before a major match. I chronoed one last time before the match and i was in the low 160s. Load was 4.7 TG 180 JHP Zero loaded short. Alway shot in the upper 170s. My son's STI and my back up STI always shoot the same load 2 pf higher.

I shoot the match w/ my SV, never was chronoed. I then chronoed the same load w/ my SV and STI's after the match and i was back up in the 170's. Not sure what it was. We chronoed other loads and guns both times and nothing seemed out of the norm.

i'm not sure but it may have something to do with Schuemann's cleaning or non cleaning recommendations. it sure seems like the dirty or seasonedarrel chonoed faster for me.

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  • 2 weeks later...

i would still use another chronograph to verify velocity, ive been fooled too many times by bad chrono readings...

Anyway, i think that chronographs are like weathermen, wrong most of the time, but an educated guess.

Harmon

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i would still use another chronograph to verify velocity, ive been fooled too many times by bad chrono readings...

Anyway, i think that chronographs are like weathermen, wrong most of the time, but an educated guess.

Harmon

Don't forget the chicken beaks, frog gizzards, and batwings, all critical components for chrono work. :lol::lol:

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