Gas Checks

[Speedluvn]

I purchased a Rossi 92 Lever action rifle in .357, with a 16 inch barrel. I'm using lead SWC bullets. Ive been trying to zero the Vortex Scout scope that I have for the rifle but have been having problems. I used a lapping tool to determine that the rings are straight on the rifle. I can hit paper at 100yards but nothing resembling "groups" for what should be considered a hunting rifle?

Will gas checks increase my accuracy?

 

[Melnic]

Did you slug the barrel? I have seen lead SWC in both .357 and .358.
I shoot SWC in a pistol but not in my lever 357 and I don't shoot it at 100yds but I can say that I know right diameter is uber important to stretch that far out.
Others may want to know what your velocity is and the base shape of the bullet is.

I have noticed gas checks on rifle bullets that are powder coated or even alox coated make a huge difference with rifles. Never gas checked any pistol bullets though to tell you that answer.

 

[Speedluvn]

Did you slug the barrel? I have seen lead SWC in both .357 and .358.
I shoot SWC in a pistol but not in my lever 357 and I don't shoot it at 100yds but I can say that I know right diameter is uber important to stretch that far out.
Others may want to know what your velocity is and the base shape of the bullet is.

I have noticed gas checks on rifle bullets that are powder coated or even alox coated make a huge difference with rifles. Never gas checked any pistol bullets though to tell you that answer.

Slug the barrel? I’ll check the diameter of bullets. I have no chronograph. I’m using Lil gun and W296 load data.
What should I expect the increased velocity to be from a rifle barrel? I’ve read 2-300, up to 500 additional fps.

 

[smdub]

Slug the barrel?

Process is the same for rifles and handguns.
https://www.starlinebrass.com/articles/slugging-handgun-barrels-identifying-proper-bullet-size/

 

[guzma393]

Gas checks by default should produce better groups as it squares any imperfections of the base of the bullet and protects the cast round from hot gases at high speeds.

Accuracy can also be explained if you are shooting a cast bullet with a gas check shank without gas checking them..shooting a GC shank based cast is basically shooting an incomplete cast round as it was designed to be fitted on with a gas check.

If they are plain based, fit is king, but also the optimal hardness of the lead will affect things if you are pushing them hot enough. What is the hardness of the casts and how fast are you pushing them?

Sent from my Moto G (5) Plus using Tapatalk

 

[Speedluvn]

The bullets that I’m using are from when my father reloaded and the bullets are approaching 35 years old or so. They’re from the National Bullet Co. I see nothing on the box that indicates the percentage of antimony.

I started with 16 grains of W296. I’m not exactly sure what the fps are since it’s being loaded for a rifle barrel.
How much more of an increase in fps should I expect coming from a rifle?

 

[Biggfoot44]

National Bullet uses industry standard " hard alloy " of aprox 2/ 6/ 92 of Tin, Antimony , and Lead . Aka approximately similar to any mass produced " hard cast " bullet .

But the alloy is just part of things , sizing , lube , and design are also major factors . Measure the bullets , sometimes Nationals run undersized .

As much as I like cast bullets , there is an obvious question to eliminate variables - How does it group with jacketed bullets ?

Let's talk actual measurments . How Big is " nothing resembling groups from susposed to be hunting rifle " ? Are we talking 4 inches ? 8 inches ? 2 feet ?

Expected velocity ? A generic industry standard 158gr JHP/ JSP should be 1700- something fps from rifle . IF your bullets are nominal 158gr , that 16.0 of WW296 should be same ballpark , maybe a hair faster .

 

[Speedluvn]

Anywhere from 8 to 10 inches. There was no “group” consistency. Holes are sporadically splattered over the target. My initial thought was that the scope was off. After verifying the scope was mounted correctly, I then suspected the bullets and the loaded ammo I was using.

 

[Biggfoot44]

Clean bbl , then test with factory jacketed ammo .

 

[Speedluvn]

Thanks. I’ll give that a try.

 

[John from MD]

I purchased a Rossi 92 Lever action rifle in .357, with a 16 inch barrel. I'm using lead SWC bullets. Ive been trying to zero the Vortex Scout scope that I have for the rifle but have been having problems. I used a lapping tool to determine that the rings are straight on the rifle. I can hit paper at 100yards but nothing resembling "groups" for what should be considered a hunting rifle?

Will gas checks increase my accuracy?

Are the bullets you are shooting made for gas checks? What kind of loads are you shooting?

 

[Speedluvn]

Are the bullets you are shooting made for gas checks? What kind of loads are you shooting?

How would I know if the bullets are made for gas checks?

I was starting on the the low end of W296 and LiL Gun data and planned to work up until I realized my sporadic groupings.

I have quite a few 158 SWC that I planned to use.

 

[John from MD]

How would I know if the bullets are made for gas checks?

I was starting on the the low end of W296 and LiL Gun data and planned to work up until I realized my sporadic groupings.

I have quite a few 158 SWC that I planned to use.

There are some pictures in this link.

https://www.montanabulletworks.com/bullet-information/

WW 296 and H110 are the same powder and are excellent for heavy hitting bullets in .357. That said, you must not deviate from the low or high recommended loads as you can get a stuck bullet or an explosion. Usually the spread given doesn't exceed 2 grains.

Hogdon only shows one Rifle load with 158 gn bullet and it is a Jacketed hollow point. The speed starts at 14xx FPS. If I were using a cast bullet at that speed, I would either want a gas check bullet or a powder coated bullet. A plain base .357 bullet may lead the barrel at those velocities.

For Lil Gun and 158gn, it only has one load for lil gun and it is a pistol load. It starts at 13xx FPS.

 

[Biggfoot44]

Above he mentioned 16.0gr of WW296 , which is a suitable load for a 158 .

As John said , bullets for gas checks are recessed around the base to accept a gas check . You can't just add a GC to a plain base bullet .

Check accuracy with a factory jacketed load . If it groups more or less acceptably , you can at least initially eliminate major issues with rifle , to focus next on load development .

 

[Rockzilla]

gas checks -- yes
here's some reading..
https://castboolits.gunloads.com/forumdisplay.php?60-Gas-Checks


-Rock

 

[GunBum]

You can't just add a GC to a plain base bullet .

Not true.

You can, and there are even special gas checks for plain based bullets if you don’t want to stage the standard gas checks onto you plain base bullet.

 

[John from MD]

Not true.

You can, and there are even special gas checks for plain based bullets if you don’t want to stage the standard gas checks onto you plain base bullet.

True. This company makes aluminum gas checks for plain base bullets and they work.

https://www.sagesoutdoors.com/

He's a great guy and has good prices.

 

[Speedluvn]

I’ll be reading the link but is there a difference uses between the aluminum and copper gas checks?

 

[Biggfoot44]

Opps , my bad ! Make that Conventional GC not suitable for plain base bullets .

I was influenced in my formative years by Elmer K. as to prefer properly designed & sized plain base , GC for unusual specialized applications , or marginally rough bores . But hey , Ray Thompson took the other view .

 

[John from MD]

I’ll be reading the link but is there a difference uses between the aluminum and copper gas checks?

Aluminum is cheaper. At one time, the aluminum checks did not adhear to the base of the bullet as well as the Hornady crimp on checks. Over the years, Sage has refined them and now they work the same.

I make my own aluminum gas checks and can't tell the difference out to 100 yards.

I believe the checks made for plain base bullets are only made of aluminum because they are thinner and have to be super soft be formed around the plain base bullet.