over bore diameter fo muzzle brake

[kennacl55]

Just put a muzzle brake on my H&R ultra. How much overbore diameter is needed to shot bullets without a sabot? It is only .007 over groove diameter now to allow the use of 40 cal. bullets with sabots. Is .007 over groove diameter large enough to shoot .452 bullets? It's a harrels brake built for shooting sabots.

[¾KlickHunter™]

If everything is concentric, you have enough clearance. If you get some powder abrasion on the ports you could run into an issue loading which would require polishing out any burrs that have developed. I’ve read about mistakes where a smith reamed a brake for 7mm and slapped it on a 30cal before heading to the range. They ended up with a rifle that wouldn’t consistently hit paper but there was no Hollywood explosion. In my opinion you are not looking at doing anything dangerous.

[kennacl55]

I shot it today for the first time since installing the brake. I only shot at 25 yards since I had the scope off for brake install. This is the best $50.00 I ever spent. All three in same hole and recoil was way better than before. This gun would jump 10" up off the front rest before the brake was added, it still has some muzzle jump but I barely noticed it. I was shooting a 10/50 4759-4198 load with 200 gr. sst in a harvester blue sabot. I want to try to shot 452 parker BE so I can shoot more in hot weather and not worry about sabots failing, just didn't know if .007 over groove diameter was enough.

[AJ]

I believe Harrell's recommends a .020" clearance for the bore of the brake over bore diameter. As fouling builds up you may start to see issues with only a .007" gap.

[kennacl55]

They sent a paper with the brake with special instructions saying .007 over groove diameter if shooting bullets with a sabot. I was kind of surprised to because it didn't say that on their website.