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Discussion Starter #1
I recently got my SP5 to MP5SD conversion back from TSC. I didn’t have a drum sight when I sent it in so once I got it back I decided to take off the SP5 sight and zero the drum sight. Shooting at 25m I am not able to get any discernible group, it’s all over the place. I’m not expecting pinpoint accuracy but 8-10 inches at 25m is completely unacceptable. I have a TPM can on the gun. Any idea what could be causing this? I have a B&T can at work I’ll grab tomorrow and Try with it, however I’m still completely befuddled by the groups I’m getting. I’m not the best shot by any stretch but the same night I shot this I shot around a 2 inch group with an APC45. The picture is at 25 yards.
 

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HK Shooting Team
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I had a TPM can with an improperly done end piece that caused the bullet to strike it.....since Mike did your conversion I’m all in saying your TPM can is the problem....TPM will fix it
 

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Some of those bullets are going the wrong direction. Seriously, that is not bad for 25m. Certainly try with a different can and as you become more familiar with the sights your pattern will shrink.
 

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Some of those bullets are going the wrong direction. Seriously, that is not bad for 25m. Certainly try with a different can and as you become more familiar with the sights your pattern will shrink.
The bullet holes going the wrong way were from 2 other guns I was sighting in. The 7 shot group in this pic is right at 9 inches wide, I could group better than that shooting buckshot at 25 yards lol
 

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It’s the suppressor or end cap. I had a similar experience with a Form 1 SD suppressor, I made while waiting for my B&T SD can to clear NFA. The suppressor would work pretty decent on my TSC MP5SD but when I put it on my APC9SD, even at 25 yards I got wild groups. Kept getting end cap grazes on the APC9SD. Your B&T suppressor should work fine. I’d contact TPM.
 

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Discussion Starter #6
With the B&T can I grouped right around 2.5 inches at 25 yards. These are my first cans (got my SOT just so I wouldent have to wait) so I’m not too familiar with them, however I think the TPM shows signs of baffle strikes? Again I’m not too familiar so I’ve attached pics below for other to look at and see what they think.
 

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I had the same exact problem with a TPM 8" suppressor. I contacted Ken @ TPM and he took care of the problem. I shot it today and had no issues with flyers or end cap grazing.
 

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With the B&T can I grouped right around 2.5 inches at 25 yards. These are my first cans (got my SOT just so I wouldent have to wait) so I’m not too familiar with them, however I think the TPM shows signs of baffle strikes? Again I’m not too familiar so I’ve attached pics below for other to look at and see what they think.
Yup you are getting contact with those baffles. Contact TPM.

How about some pics of the SD, I have an HK94 with TSC waiting on an SD conversion. Would love to see yours
 

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Here is an idea from the peanut gallery. Get yourself a tight tolerance tool steel rod and slide it into your expensive gun/suppressor before you fire it. It just seems to me that using a live round to test your concentricity is a very high risk operation.

As a gesture of goodwill, I will point you to part number 8893K231 from McMaster-Carr. The OD is .3438 to within +- .0005.

I don't have a dog in the fight. I don't know this TPM outfit. But this all seems very odd to me. Very odd indeed.
 

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I had the same exact problem with a TPM 8" suppressor. I contacted Ken @ TPM and he took care of the problem. I shot it today and had no issues with flyers or end cap grazing.
Glad I am not waiting on one of those. How hard can it be to make a reflex suppressor cocentic?!? Particularly since OP's gun presumably used a genuine H&K barrel.
 

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Glad I am not waiting on one of those. How hard can it be to make a reflex suppressor cocentic?!? Particularly since OP's gun presumably used a genuine H&K barrel.
Much like biology, there is a male, and a female. Is the fault all with the male? All with the female? Or possibly a stack of issues all in the same direction.

All that said............a live round does not an alignment gage make.
 

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Much like biology, there is a male, and a female. Is the fault all with the male? All with the female? Or possibly a stack of issues all in the same direction.

All that said............a live round does not an alignment gage make.
It's pretty clear the problem is the TPM suppressor, and not the German barrel which worked fine with the B&T suppressor.
 

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I have a factory SD (pre-86 DS). Extremely accurate at 25 yes. Zero issues. The guns are capable of extremely good performance at 25 yds. I dont have any experience w conversions. Good luck!!
 

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Thinking about this, it sounds like perhaps a malalignment of the suppressor with the bore axis. Is there any evidence at all of the rounds impacting the muzzle end of the suppressor?

Agree that it sounds like the can and not the barrel assuming that there has been no damage to the crown.
 

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Call TPM - they are good guys and will take care of this if it is due to their can.
 

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The problem has been identified. It is the actual suppressor and is a known issue. For whatever reason, at least one run of TPM SD suppressors had some pretty significant alignment and concentricity issues. These problems are acknowledged and are being addressed by the manufacturer.
 
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