Trimming advice

[Shrek]

I have 280 pieces of new 7mm wsm brass I'm beginning to process and the book trim lenght is 2.096 but only about 10 pieces of the first bag would be trimmable to that lenght with most pieces falling between 2.092 to 2.094. Normally I would just trim to the shortest lenght and that is what I will probably do since this brass is virtually unavailable but what are the negatives of trimming everything to 2.09 and calling it good ?

 

[Dusty Stevens]

Itll be fine.

 

[Shrek]

Thanks , I know I can get away with it but I'm tying to be a better loader so if anyone knows of any drawbacks to trimming 5 to 10 thousandths short I'd like to know.

 

['Freak]

Unless you’re going to perform some case prep operation that indexes off the case mouth so all need be the same length, shoot ‘em once then trim all to the shortest length after their first time through the size die.

 

[Shrek]

I was planning on running them through the fl bushing die and then trimming and skim turning the necks to clean them up. The flash hole deburr and weight sort into 1% batches.

 

[Dusty Stevens]

As long as theyre shorter than reamer print trim length its cool. Most folks trim .010-.015 shorter anyway

 

[Webster]

After shooting a few times they may grow to the book trim length?

 

[zipollini]

If I run my brass thru a FL size die with a neck bushing my brass length usually grows about .003" which usually solves any short brass problems.

 

[Sniper338]

Unless you’re going to perform some case prep operation that indexes off the case mouth so all need be the same length, shoot ‘em once then trim all to the shortest length after their first time through the size die.

This. Shoot em once before trimming

 

[jcampbellsmith]

I have 280 pieces of new 7mm wsm brass I'm beginning to process and the book trim length is 2.096 but only about 10 pieces of the first bag would be trimmable to that lenght with most pieces falling between 2.092 to 2.094. Normally I would just trim to the shortest lenght and that is what I will probably do since this brass is virtually unavailable but what are the negatives of trimming everything to 2.09 and calling it good ?

Shoot them all. Trim to 2.096. Regards JCS

 

[Joe R]

Daveinjax said:
....what are the negatives of trimming everything to 2.09 and calling it good ?

The negative is that over time you may develop a carbon ring in front of the case mouth. If left unattended the carbon ring becomes hard and difficult to remove. It may affect bullet release and/or accuracy down the road. However, if you are careful to give the chamber a little extra attention you should be able to keep it clean. If don't have a borescope get one they can be had for around $20 these days.

See http://www.ebay.com/itm/like/171743623863?lpid=82&chn=ps

Kindest regards,

Joe

 

[Terry Altom]

Thanks Joe! I had no idea I could get a borescope for $20.

Do you or anyone else happen to know the minimum focal length of the one from eBay?

This one on Amazon says 3cm is the minimum. Ebay is three weeks to deliver. Amazon is two days.

http://www.amazon.com/Diameter-Waterproof-Endoscope-Borescope-Inspection/dp/B00N4L5N4A/ref=pd_sim_sbs_147_3?ie=UTF8&refRID=0FF2RWSFVM081WYRJF7N

Thanks,
Terry

Daveinjax said:
....what are the negatives of trimming everything to 2.09 and calling it good ?

The negative is that over time you may develop a carbon ring in front of the case mouth. If left unattended the carbon ring becomes hard and difficult to remove. It may affect bullet release and/or accuracy down the road. However, if you are careful to give the chamber a little extra attention you should be able to keep it clean. If don't have a borescope get one they can be had for around $20 these days.

See http://www.ebay.com/itm/like/171743623863?lpid=82&chn=ps

Kindest regards,

Joe

 

[mikecr]

There is no reason to trim em all to the shortest length, and no reason to trim em all to some book value.
Why don't you measure your chamber length with a gauge, and trim to an appropriate value when you get there?

 

[Joe R]

Thanks Joe! I had no idea I could get a borescope for $20.

You are welcome Tom,
Here's a link from last months postings where the $20 bore scope topic was discussed. A couple respondents already had one.
http://forum.accurateshooter.com/index.php?topic=3875473.msg36586895#msg36586895

When I use mine I put a black glove over the muzzle so there is no back light to create problems. I also use a q-tip with alcohol to clean the lens. The fiber-optic lens and cable is water proof.

Joe

 

[jimhoodag]

Joe,

I can't afford a Hawkeye bore scope and am interested in one these you linked to, but have read some derogatory remarks on this site about them. Have you used one of these type of borescopes on rifle bores?

Jim

 

[barefooter56]

Daveinjax,
Sinper338 and Mikecr have it nailed. Chamber length gauge is available through Sinclair International. Part number is 749-000-784. This little gauge can save you a lot of case prep time as far as trimming is concerned.

 

[Joe R]

jimhoodag said:

Joe,

I can't afford a Hawkeye bore scope and am interested in one these you linked to, but have read some derogatory remarks on this site about them. Have you used one of these type of borescopes on rifle bores?

Jim

Jim,
A word to the wise: there are cyber shills (definition: A shill, also called a plant or a stooge, is a person who publicly helps a person or organization without disclosing that they have a close relationship with the person or organization) all over these boards and the internet in general.

I assume that Hawkeye has a shill (with multiple handles) here to protect it's interest. So take the criticism with a grain of salt. If you're a gunsmith and need to see crackling in the throat of a barrel then you should probably buy an Hawkeye, but if you're like me, a shooting junkie, then these bore scopes are more than adequate to look in the bore and chamber to see if your barrel is as clean as you want it.

I also use mine t scope my barrels before I get them chambered. So far I haven't found a bad one yet.

Kindest regards,

Joe

 

[Webster]

Just received my borescope from Amazon in two days. It’s disappointment. The brand name isn’t on the box or instructions. If you aim it straight down on something on your desk top it gives a good image. Problem: it looks straight down the center of the bore giving a poor image of the bore surface. Needs a 90° view? Any tips on its use? I have been saving pix in the movie mode, need to figure out how to capture as a picture. The reason it’s $20 is that it’s just the camera, cable and software. It has to be attached to a computer by USB port to see and capture images. This isn’t a problem for me as long as I can judge the bore condition and look for a carbon ring.

 

[Joe R]

Webster said:

Just received my borescope from Amazon in two days. It’s disappointment. The brand name isn’t on the box or instructions. If you aim it straight down on something on your desk top it gives a good image. Problem: it looks straight down the center of the bore giving a poor image of the bore surface. Needs a 90° view? Any tips on its use? I have been saving pix in the movie mode, need to figure out how to capture as a picture. The reason it’s $20 is that it’s just the camera, cable and software. It has to be attached to a computer by USB port to see and capture images. This isn’t a problem for me as long as I can judge the bore condition and look for a carbon ring.

I didn't meant to hijack this thread and I apologize if it offends anyone.

Webster, as I mentioned in my other posting, I don't have the $20 bore scope. I have the one pictured below, so I can't help with details on jpeg capture. But if you can see it on your computer screen all you have to do is use the Snipping Tool utility to do a screen capture. The Snipping Tool is included with Windows 7 and is located in the Accessories folder.

Regarding getting a better image with the cable, I put a black glove over the muzzle to prevent any back light. My borescope allows me to adjust the brightness of the LEDs, I don't know about yours. Looking straight ahead is what you want to do. You can see enough detail (copper, gouges in the rifling, carbon ring, etc...). I have a 90 degree mirror and used it only once, that's because it is like walking around with blinders and looking at your feet. You have no idea where you are, where you've been and where you're going. A real waste of time.

If you're really fixated on the 90 degree mirror, see if the tip of the bore scope has a threaded sleeve. Mine does, if it does then you can look for a 90 degree mirror.

Kindest regards,

Joe

 

[waldo1979]

The negative is that over time you may develop a carbon ring in front of the case mouth. If left unattended the carbon ring becomes hard and difficult to remove...

Nailed it. Those carbon rings are killer to remove.