Lands to deep?

[stretchman25]

I have a .62 caliber rifle with a 1 in 66" twist and .014 deep lands. For years I wondered why patches continued to have blow by, or burn through, until I measured the bore and determined the depth of the lands. The bore measures .620 from the tops of the lands and .648 from the bottom of the grooves. I am currently using .020" thick cotton patching with an over the shot wad over to try and minimize patch damage, but still burn patches with a .615 round ball. Does anyone know where I could find thicker patching material, or have any suggestions for load development?

 

[coloradoclyde]

Show us some pictures of patches with blow by..

Joanne's or even Walmart. for fabric....but I suspect something else it at play.

 

[Vaino]

A pic of the patches would do wonders in determining whether it's blowby or burning. Blowby is possible because of only .0035 patch compression in the groves and burning might be caused by insufficient amount of lube or the wrong lube. Also, patch mat'l could be the culprit.

Calculating a .615 RB plus .040 double patch thickness equals .655 minus a groove dia. of .648 yields a patch compression of .0035 in the grooves.

If the wad is a tight fit in the bore, it might not be filling the grooves. I think what you're complaining about is a normal situation for a MLer. Again, a pic of the patches would be helpful. PRBs don't need a wad and I have never used one and my experience bears this out.

I agree that .014-.016 groove depth is too deep....008-010 deep works fine w/ my super accurate Douglas bbled LR shooting PRBs......Fred

 

[mooman76]

What are you using for patch material? Could be it's old or not strong enough. You can use cotton denim for a patch. It can be thicker and it is generally real strong.

 

[Spikebuck]

I have a Rice barrel with .016 deep round bottom grooves and .620 land to land. That makes .652 groove to groove.

I shoot a .610 ball and .025 thick ("my" crushed measurement) denim patching I make from material I got at a Wal-Mart. With the ball wrapped in the patch, that's .660 with my "crush" measurement (obviously the actual loading can crush it more than the pressure I apply in my measurement). Once I found what worked I went into the store with a calipers and measured bolts of denim until I found what I needed. That load takes several hard whacks to get started and you have to work it down with the rod (in fact after breaking a wood rod I put a brass rod on that gun) with a few strokes, but it's very accurate with either Dutch's water/ballistol mix or Track's Mink Oil. No burning.

At one point in my load workup I was using a wad too. But, it's one additional component you should not "need" to have. Good luck as you continue to work on this.

 

[ohio ramrod]

I use an over powder leather wad to prevent blow by, burned patches, or heavily lubed pacthes or mini's from fouling the powder. :idunno:

 

[M. De Land]

Try some .018 cotton felt patches. I have found it to be the best patch material I have ever used.

 

[Wes/Tex]

Does anyone know where I could find thicker patching material, or have any suggestions for load development?

Yep...it's called chamois leather! :wink: Check with leather wholesalers or waait till your local auto parts stores have a sale on chamois drying piece sales. It's magic! :haha: Thicker but compress better than cloth, fills rifling cuts better, doesn't smolder on ground adn usually can be licked off and reused! Well, maybe not licked! :rotf:

 

[Zonie]

"Licked off" ? :shocked2:

"See Phoebe Anne? Ah tol ye em Texicans are weird." :wink:

 

[curator]

I have had this problem with my .52 caliber Hawken that has grooves .015 deep. Double patching and thick blue jeans fabric did help. So too did loading a 28 gauge "over powder" card wad on top of the powder charge. The best thing I found to prevent patch burn through with easy to load patch/ball combinations wad a half measure of Cream of Wheat on top of the powder charge. My usual charge is 75 grains of FFg followed by 40 grains of COW, then .520 round ball and .018 pillow ticking patch. Not only does the COW seal the bore and prevent patch burn through, but the bore shows significantly less fouling and accuracy is outstanding. Better in fact than using any other method. The down side is handling two powder measures and two flasks and the possibility of mixing them up.

 

[Rifleman1776]

Others have said it. There is something else at work here. Your ball/patch combo sounds like it should be OK. Is the lead you are using soft? Grooves are deep but not TOO deep. hotoSmile:

 

[coloradoclyde]

"Licked off" ? :shocked2:

"See Phoebe Anne? Ah tol ye em Texicans are weird." :wink:

Phoebe Anne?....Moses?
I use to party with her back in the day...
That girl could shoot.... :grin:

 

[hoochiepapa]

My "super-duper accurate" .54 Lancaster with a Getz barrel was burning patches, and accuracy suffered. I bought some Ox-yoke wonder wads at the suggestion of someone here, and land sakes if that didn't make a difference. I had 3-4 inch groups off-hand at 25 yards, they tightened to three shots touching.

 

[Pete G]

Sounds like you need a thicker patch. Denim usually works well in this type situation, but wash it well to get it soft enough to accept the lube.

 

[hanshi]

An op wad, be it felt, leather or a wad of paper goes a long way in preventing patch burns caused by blow-by. I have two Rice round bottom barrels, a .50 and a .32. These round grooves are .016" deep and like a thick patch; they also like op wads. Grooves of .016" are fairly deep but far from being too deep.

 

[stretchman25]

I will try and figure out how to post pictures, but in the meantime I purchased .020 linen, .025 canvas and .027 denim that I plan on testing Monday morning. I also found some 19 gauge 1/8" wads that I will try as well. Thanks to everyone who helped by offering suggestions and past experiences.

 

[Bob J]

stretchman - My Rice .62 barrel has deep grooves and it took me awhile to find the best load. Wes/Tex's suggestion of chamois works very well for with a light (50 gr 3f) offhand practice load and is so easy to load that the ball and patch can usually be thumb-started. Accuracy with a full power hunting load is OK at 50 yards, though I do get some fliers. The lube is Eastern Main Product's lube (which is the same as wonder lube). I will use the chamois for quick reloads in the field and offhand practice. For the best accuracy, I have found that Track of the Wolf's .020 wonder patch (wonder lubed) groups well and has eliminated fliers with full hunting load, which in this .62 is 100 grains 2f Goex.

 

[Vaino]

After reading all the posts, it seems there are complications w/ the deeply grooved bbls {.016}.
Finding the right combination for an accurate load is a whole lot easier w/ a bll w/ .008-.010 deep grooves....sealing off the grooves is definitely a lot better. This eliminates the need for an excessively thick patch and/or OP wad which is an unnecessary component to fiddle w/.

Why the bbls are grooved .016 deep is beyond my comprehension seeing .008-.010 deep grooves work well w/ PRBs.....Fred

 

[zimmerstutzen]

Try a really heavy cotton flannel. Not the cheap stuff discount flannel shirts are made of. I have had really good luck using heavy flannel for years,

 

[stretchman25]

I was able to get to the gun club yesterday and test linen, canvas and denim. The .020 linen patches were nearly completely torn apart and burned up when recovered. The denim worked well, but the .025" canvas patches were better. They showed no signs of burn through or blow by. The recovered patches looked as if they could be reused. I will start developing a load with the canvas for patching in the next few days.