Patch Thickness Variation

[Ken Rummer]

I cut strips of 10 oz denim and chopped them into squares of 1.25" for my 62 cal rifle. With all the posts about Dutch's method and how important patch thickness was, I decided to measure the thickness of each patch. I mic'ed the center and used the clutch on the mic barrel to get even patch compression. I rounded to the nearest .001. I found the following:

14 patches .024 thick
53 patches .025 thick
43 patches .026 thick
7 patches .027 thick

This piece of denim had a variation of at least .004. I sorted them by thickness and went to the range. Normally I have been getting 3.5" at 50 yds. with patches not sorted by thickness.
I shot 3 shot groups with three different sorted patch thicknesses and each one was better than the unsorted results and averaged around 2".

My rifle barrel is .620 land and .644 groove.
I lubed the patches with Stumpy's moose snot.

The .026 patch compressed .004 in the groove and .016 at the land. It was hard to load but shot a cloverleaf.

The .025 patch compressed .003 in the groove and .015 at the land and was easier to push down and shot 2".

The .025 patch compressed .002 in the groove and .014 at the land. It was a pleasure to load and shot 2".

I did not clean between shots, which is why I like moose snot. None of the patches had holes.
MY load was a .600 Eddie May RB over 90 gr Goex 3F.



Commercial patch material can have large variations in thickness. There is probably no such thing as a good bolt of material.

Measuring and sorting individual patches will result in better groups

The biggest suprise was you don't need a lot of patch compression in the groove.

 

[roundball]

Some additional info on patches.
I mic'd sample patches from bags & bags of Oxyoke precut / prelubed patches over a lot of years, and found their consistency very stable within bags.
And mainly for that reason I've always stayed with those manufactured by Oxyoke, regardless of what actual retail label they end up under on a shelf...Oxyoke themselves of course, plus T/C, Traditions, CVA, Remington, etc.

What I also found is that the Oxyoke tight weave solid color cotton often measures .002" thicker than labeled...for example, .020" actually measures .022"
Yet bags of their pillow ticking that might be labeled .018" actually measure .018"

After discovering that several years ago, the first thing I do when I get in a new shipment of patches is pull 4 random sample patches from each 100 count bag, measure them, and write the 'actual' on the label...either confirming what they're labeled, or indicating the correct thickness.

But so far, the only trends I've found are:
1) Pillow ticking measures as labeled, but the tight weave cotton measures .002" thicker.
2) Measurements have always run true for the entire contents of a bag, never found variations within a bag.

 

[Dphar]

I cut strips of 10 oz denim and chopped them into squares of 1.25" for my 62 cal rifle. With all the posts about Dutch's method and how important patch thickness was, I decided to measure the thickness of each patch. I mic'ed the center and used the clutch on the mic barrel to get even patch compression. I rounded to the nearest .001. I found the following:

14 patches .024 thick
53 patches .025 thick
43 patches .026 thick
7 patches .027 thick

This piece of denim had a variation of at least .004. I sorted them by thickness and went to the range. Normally I have been getting 3.5" at 50 yds. with patches not sorted by thickness.
I shot 3 shot groups with three different sorted patch thicknesses and each one was better than the unsorted results and averaged around 2".

My rifle barrel is .620 land and .644 groove.
I lubed the patches with Stumpy's moose snot.

The .026 patch compressed .004 in the groove and .016 at the land. It was hard to load but shot a cloverleaf.

The .025 patch compressed .003 in the groove and .015 at the land and was easier to push down and shot 2".

The .025 patch compressed .002 in the groove and .014 at the land. It was a pleasure to load and shot 2".

I did not clean between shots, which is why I like moose snot. None of the patches had holes.
MY load was a .600 Eddie May RB over 90 gr Goex 3F.



Commercial patch material can have large variations in thickness. There is probably no such thing as a good bolt of material.

Measuring and sorting individual patches will result in better groups

The biggest suprise was you don't need a lot of patch compression in the groove.

Y

TYPO

 

[Dphar]

Tight loads invariably shoot better.
I would try several 5 shoot groups to confirm.
Three shot groups are easier and I am guilty of using them but they are more susceptible to what a friend calls the "law of compensating errors" where an error in the load can be cancelled by an error in holding or sighting.
But a 3 shot cloverleaf? That's a good place to start testing.
Also it does not take much breeze to move a RB 1" at 50 yards.

Dan

 

[Stumpkiller]

I'd be sorting out those 0.026" patches for special occasions.

I've gotten lazy and non-competitive in my practices and prefer the "It was a pleasure to load and shot 2"" type shooting anymore. ;-)

 

[Ken Rummer]

The .026 will be the one I load at home and take hunting. The .024 will be in my bag for second shots if required.

Thanks for the juice and snot recipes. They are two great lubes.

 

[nw_hunter]

Ain't it the truth!I haven't pounded one down the barrel in a while.The older I get, the more I prefer easy. As long as it don't roll back down the barrel, I'm happy. :wink:

 

[mjac]

Ain't it the truth!I haven't pounded one down the barrel in a while.The older I get, the more I prefer easy. As long as it don't roll back down the barrel, I'm happy. :wink:

I ain't been here long but that's the same conclusion I came to. :surrender:

 

[Vaino]

My "super" accurate squirrel LR evidently "digests" patches and RBs w/ slight variances, because I never measure and sort either. Upon purchase, both patch mat'l and RBs are measured to ascertain that they're the correct size, but no comparison w/in a box of RBs is made and I assume that the patch cloth mat'l is of uniform thickness. Done this for many yrs w/o an accuracy problem......Fred

 

[Rifleman1776]

We ain't dealing with scientific tolerances. Fer peety's sake.
We are shooting dirty old muzzle guns. Fret a thou difference in patch thickness and ye'll never have any fun.