Meplat uniforming - how much is too much?

[OneEyedJack]

I've got three different types of meplat uniformers, but all raise the same question: How much is sufficient to uniform the BC without degrading it by more than the 2% or so that has been claimed?

The problem lies in the differences in length from the ogive, where the uniformers are indexed, to the tip, where the cutting occurs. Even with bullets from the same box that have been matched in bearing length,175SMKs and 115DTACs, for example) there are "significant" differences in how much gets trimmed.

At the moment, I am setting the blade to trim about 7/8 of the meplat circumference in the average bullet. This reduces the highest points on the meplat, but leaves the lowest uncut. Some bullets are fully uniformed while others are untouched by the cutting blade.

Without having shot any uniformed bullets yet to 1kyd, I am reluctant to trim more for fear of substantially reducing their BCs.

So, how much is enough and how much is too much to cut? What's your experienced advice?

 

[tightneck]

Any of you seeing any significant reductions in group sizes that you attribute to meplat uniforming??? How many of you long range F-Class and BR shooters are uniforming?

 

[sparker]

My question about meplat uniforming all along has been, is there any discernable difference in group size between bullets that have been uniformed versus those that have been sorted by ogive length? I want to see real data here not anecdotal evidence, but double blind testing. Five groups of each shot at 1000yds and then measured for vertical would be a good start.

Scott Parker
Bakersfield CA

 

[aJR]

I shoot Long Range BR in Australia,probably check,adjust,trim and qualify at more points in both the brass and bullets than anyone in my country ..I will not shoot a bullet in testing or competition that has NOT been Meplat Trimmed, One of your best shooters and gunsmiths in Dave Tooley has stated the the exact same thing .. I have proved if only to myself that the aggregates get better with meplat uniforming,mabye his helped me get to the AUST Shooter Of The Year in 2006,i don't know but it certainly didn't hinder it ..All the little fiddly things we do IMO help,my fellow competitors are starting to think the same way..JR..Jeff Rogers

 

[sparker]

Rewinder,

I think you missed the point. The question was how do the uniformed groups compare with the ogive sorted groups. Provided that we are not shooting in a heavy head/tail wind that switches 180 degrees, the vertical dimensions of the groups should be comparable in regard to conditions.

The reason that I suggest double blind testing is to remove the placebo effect. For those of you who think that this does not occur in shooting, think again. There have been records shot with practice ammo by mistake.

Scott Parker
Bakersfield CA

 

[Forum Boss]

Scott,

Jason did some testing with uniformed meplats vs. regular and closed meplats vs regular. It his experience, if I understand correctly, the uniforming,shaving) didn't help that much.

On the other hand, closing up the meplats on Jason's Clinch Rivers resulted in noticeably less vertical at 1000 yards. Also average group size was smaller.

Hopefully Jason will chime in here as I'm just summarizing what he told me a while back.

 

[dreever]

All,

I think it depends on the bullets in question. Lets face it some custom bullets are made better than others, and this goes double for the mass produced variety.
In my own experiences playing around with various bullets I've found that the most notable difference will be at 500 yards and beyond. At the short ranges I don't see how you can tell.
Take any box of bullets and start looking at the Meplats under a magnifying glass and it will quickly become apparent if trimming Meplats will make that much of a difference.
Personally I'm anal, and anything that might shrink those groups no matter how small I'm willing to do for those longer range targets.

Danny

 

[jb1000br]

I have a few things I can report...one being: I still can't tell if meplat trimming helps by looking at my groups.

While my 6BR was shooting well...after our World Open,shot only UNtrimmed bullets there) I tested some trimmed bullets...I would alternate trimmed and untrimmed bullets for the last half of the season.

I had two groups that were noticable flat in the vertical plane...and I wish I could say they were both with trimmed meplats...but they weren't. One was trimmed, one was untouched.

Also with regarding the 106CR:

trimming meplats loses you 1.75MOA at 1025yds
Closing meplats GAINS you 1.75MOA at 1025yds

Hope to test some more this year.

JB

 

[tightneck]

JB, I think I remember that Ferris Pindell had made up a special die to close up meplat's. What is your method for closing them up?

 

[jb1000br]

tightneck - Pindell's is the ONLY way...

JB

 

[OneEyedJack]

For those with positive results from meplat uniforming, how much do you remove from the tip?

I'm using a Giraud meplat cutting tool, if that makes any difference in your reply. I'm removing an average of 0.004-0.005", then finishing with a few light strokes of an old carborundum stone that my dad left me 28 years ago. No range time yet with the uniformed 115DTAC bullets.