The 5P comparator

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Ovenpaa
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The 5P comparator

#1 Post by Ovenpaa »

I was recently asked if I could build a dedicated lower tool for our 2P comparator series.

The current 2P set comprises of the original 2P which measures the OAL from case head to Ogive plus base of boat tail to upper bearing surface at the point the bullet engraves the lands.

There is the 2P BSC (Bearing Surface Comparator) Which again measures the OAL from case head to Ogive plus the bearing surface of the bullet.

Finally there is the 2P Bump upper which measures the distance from case head to shoulder and is used to determine and confirm shoulder bump.

The 5P addition is a variation of the standard 2P lower which you would also use to compare base of boat tail to upper bearing surface however there was some concern that the user may not be holding the bullet perfectly perpendicular to the base which may lead to some parallax error so I machined a prototype lower which has a hole bored 8,5mm deep and sized to precisely accept the bullet. This addition should speed the time taken and accuracy of batch comparisons of bullets considerably. I ran a series of ‘before and after’ tests myself and did see a very slight improvement in results however I am used to handling measuring equipment on a daily basis so I would really hope I would get things right! One thing I did notice is it is considerably easier and quicker to drop the bullet into the location and close the calipers.

I will have a think about the pricing and marketing of the 5P addition as it is an additional operation to complete and is a variable as it is dependant on the form of the bullet to be checked. I am inclined to think it will be either available as a fifth item if requested (Hence the description/name of 5P) or as an alternative to a lower.
5P.jpg
/d

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Alpha1
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Re: The 5P comparator

#2 Post by Alpha1 »

Ill take one in 6.5x55 and .222 remington please.
I would also like a 6.5x55 shoulder bump gauge I am using Lapua cases. :good:
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Ovenpaa
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Re: The 5P comparator

#3 Post by Ovenpaa »

I will PM you on this as you have some options.
/d

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