Barrel Crowns and Accuracy

[Roy Rogers]

Attached for those interested in rifle accuracy are two articles from Precision Shooting magazine: "The Over-Rated Crown," measuring the effects of progressively severe damage inflicted upon a rifle crown; and "Crown Contortions," testing a few popular crown shapes. In brief, condition and shape of crown were discovered to have less than expected, if any, effect upon accuracy. The articles are attached as uploaded .pdf files (let's see if this works). Screen shots of the magazine covers and article first pages below. Unfortunately, Precision Shooting hasn't been published for several years.

 

[mac1911]

One of the old timers at my club would always say.
You and most cant shoot well enough to see a difference in crown wear.
He was pretty good at backing up his statements.
One day he brought NM M1 Garand to cmp . One guy was complaining his M1 was not shooting well because of the crown. Old smart man said , use my gun. Well you can guess the other guy was not thrilled when he did not shoot any better.
I have some old 22s with some damaged crowns and i dont think even with the best recrown they will shoot any better. Unless its really damaging the bullet on exit.

It is nice to look at your muzzle and see a nice crown though.

 

[Drix]

It is nice to look at your muzzle and see a nice crown though.

This is just common courtesy to the perp.

 

[gerrycaruso]

There's a lot of talk about being so careful of the crown while cleaning but I'd like to relate something my son told me. As anyone who's been in boot camp knows, the DIs were very creative in finding ways to ruin your day. My son and his buddies used a nail to scrape the carbon off the muzzles of their rifles and they all shot fine. I don't recommend that technique but it seems the crown can take a bit more abuse than we think.

 

[Davidk]

It all depends on your goals. It will effect those shooting 1/4 inch groups more than it will effect those shooting 6 inch plates at 100 yards

 

[greencobra]

huh! i'll be damned! good articles.

i was never much of a rifle shooter and never discussed the discipline much with those that did. but i did watch matches (remember the ones at camp curtis?) and noticed the crown configurations on the rifles. there never seemed to be one set way for a muzzle crown. i did see what looked like 90 degree crowns. i use to call them "not crowned) and several varying degrees of crown angles down the firing line. i'm thinking now we were witnessing the crown of the week. whoever was shooting the smallest groups at the time, well, his crown angle was the way to go. discipline and skill had nothing to do with it.

 

[whatluck]

It has to be a gouge with a significant amount of material missing from where the crown meets the bore to cause an issue. I've inherited a few field guns that look like they were used as hammers and fire pokers, and still shoot straight.

 

[mac1911]

There's a lot of talk about being so careful of the crown while cleaning but I'd like to relate something my son told me. As anyone who's been in boot camp knows, the DIs were very creative in finding ways to ruin your day. My son and his buddies used a nail to scrape the carbon off the muzzles of their rifles and they all shot fine. I don't recommend that technique but it seems the crown can take a bit more abuse than we think.

Also to add the Garand Collectors Association did a cleaning rod test on some M1 garand barrels trying to ruin the crown . I would have to find the article for specifics but the concluded it was unlikely to wear out a crown from cleaning.