OCW method - 303br - switch flat base 180gr bullets?

[RonR]

After firing some different primer and powder combinations with my sons 303br, it's showing a bit of promise and I am starting to take this rifle a bit more seriously in terms of load development. Fire formed brass seems to be making a difference.

To date we have completed some ladders with 4 different powders (and then recently from those original 10 shot results) shot 5 shot ladders around the promising charges in smaller step charge amounts with the campro 180's. There are two combinations that are hard to ignore.

These are flat base bullets. I have 100 Speer 180 flat base and 100 Sierra 180 flat base to try out as well.

My question is, if I now incorporate OCW methods around the results of the 10 and 5 shot ladder tests, can a person interchange a different flat base 180 gr and use the previous results to continue on?

This is a No 4 Mk 1/2 with a sporter stock and elevator site that seems to be on. I am not a gunsmith by any stretch but the barrel on it doesn't appear factory. Different finish on the barrel from the receiver.

Not looking for a big philosophical discussion at this point however my understanding of Dan Newberry's explanation is that the charge amount should be tolerant in keeping within parameters. My interest, for those more experienced here, is whether switching fb bullets is outside of parameters for this method of load development.

If my understanding of OCW is incorrect in relation to this situation then I'd like to know that as well. If I can apply it to similar design bullets for different chambering's it's something I would throw into the arsenal of load development in the future.

Regards
Ronr

Givens
- entering 5th year reloading
- hunter primarily that is addicted to developing loads, learning, and shooting paper in the off season with his kids
- neck turn and anneal and all that stuff for factory hunting rifles...to solve reloading process issues...not because I thought I needed to do it.
- Mystic's load development has worked very well for rifles we own in the past. Ladder testing is simply satisfying curiosity if the two different methods can arrive at the same results.
- Going off script, I want to experience for myself what other powder/primer/bullet weight combinations would work instead of the tried and true combinations that are available.

 

[cosmic]

Well - I shoot a lot of 303 in LE sporters, here are some general observations.

1) Generally flat based bullets function better than boat-tails.
2) A given rifle will "tune" to a specific bullet weight. For 303 you don't have a lot of choices..
3) I use Hornady 150 SP and 180 RN (0.312 in !). I do a trial with each bullet, 30 thou bullet jump, min load plus 1 grain RE-15. 100 y test, 5 shots, let barrel cool well between shots.

I find that the results are quite dramatic. A given rifle will immediately show preference to one of the bullet weights, right out of the gate. On occaision, I try to tune to the poorer bullet weight by playing with charge weight, powders, bullet jump, etc. without much luck.

HTH...

BTW - Pressure at the fore-end has a major effect on LE sporter accuracy, particularly # 4's which don't have a barrel band. #4's were not designed to have an unsupported fore-end, and sporters tend to develop slop over time (eg hunting sling pulling on the fore-end) This can easily be the governing limitation on accuracy.

 

[bigedp51]

RonR

There are two methods to tune a rifle for accuracy, meaning controlling barrel vibrations.

1. Tune the ammunition to the rifle by adjusting the powder charge.
2. Tune the rifle to the issued ammunition, like they tuned the Enfield rifle.

The No.4 Enfield rifle was to have 2 to 7 pounds of up pressure at the fore end tip. And the amount of up pressure was adjusted to get the best accuracy. And the draws area at the rear of the fore stock is where you adjust the up pressure. The Enfield rifle only has one bedding screw and the draws area acts like the missing second bedding screw. Meaning the draws area must be tight and not allow the fore stock to flex or move and change the amount of up pressure at the fore end tip.

"But" the No.5 Jungle Carbine had a free floating barrel with its shorter fore stock and no up pressure point. Meaning using both tuning methods can be required on a sporter Enfield.

 

[RonR]

RonR

There are two methods to tune a rifle for accuracy, meaning controlling barrel vibrations.

1. Tune the ammunition to the rifle by adjusting the powder charge.
2. Tune the rifle to the issued ammunition, like they tuned the Enfield rifle.

The No.4 Enfield rifle was to have 2 to 7 pounds of up pressure at the fore end tip. And the amount of up pressure was adjusted to get the best accuracy. And the draws area at the rear of the fore stock is where you adjust the up pressure. The Enfield rifle only has one bedding screw and the draws area acts like the missing second bedding screw. Meaning the draws area must be tight and not allow the fore stock to flex or move and change the amount of up pressure at the fore end tip.

"But" the No.5 Jungle Carbine had a free floating barrel with its shorter fore stock and no up pressure point. Meaning using both tuning methods can be required on a sporter Enfield.

Thanks Ed. I've never had it explained like that before. I learned something.

Regards
Ron

 

[RonR]

Well - I shoot a lot of 303 in LE sporters, here are some general observations.

1) Generally flat based bullets function better than boat-tails.
2) A given rifle will "tune" to a specific bullet weight. For 303 you don't have a lot of choices..
3) I use Hornady 150 SP and 180 RN (0.312 in !). I do a trial with each bullet, 30 thou bullet jump, min load plus 1 grain RE-15. 100 y test, 5 shots, let barrel cool well between shots.

I find that the results are quite dramatic. A given rifle will immediately show preference to one of the bullet weights, right out of the gate. On occaision, I try to tune to the poorer bullet weight by playing with charge weight, powders, bullet jump, etc. without much luck.

HTH...

BTW - Pressure at the fore-end has a major effect on LE sporter accuracy, particularly # 4's which don't have a barrel band. #4's were not designed to have an unsupported fore-end, and sporters tend to develop slop over time (eg hunting sling pulling on the fore-end) This can easily be the governing limitation on accuracy.

Interesting experience and tests regarding preferences to bullet weights. I'm going to have to incorporate that. Thanks.

Noted on the .312 dia bullets from Hornady occupying a bit more space.

I have got to ask you though, just to align with what I'm after. Once you have determined your preferred bullet weight and settled on a charge...would you ever consider changing from say a Speer fb 180 to a Sierra fb 180? i.e. like switching primers? Or would you redevelop the load from the start? (hornady 180 is larger in diameter...I would not consider swapping that with a Sierra or Speer.)

Thanks for your time Cosmic.

Regards
Ron

Regarding the accuracy, the barrel seems aftermarket which seems unusual I know. It may have some unique characteristics.

 

[cosmic]

RonR - I'm not sure that the OCW methodology works well with the average LE sporter, or off the shelf hunting rifle, for that matter. What I'm saying is that a given rifle may not "tune" well to charge weight, on a repeatable basis, to justify the time and expense.
Accordingly, once I've found my preferred bullet weight, I may go up a grain to see the effect, but that's about it. I don't push 303's to max load (easier on barrel and brass, and too many years in engineering school learning about metal failures).

To answer your question directly. If a given rifle prefers FB 174 gr Hornady's, the it will likely shoot 180 gr FB Sierra's well.. All bets are off if you go to boat-tails, or slightly undersize bullets (eg 3105 in dia..)

In closing, I guess what I'm trying to say is that charge weight tends to be a "least" variable, compared to bullet weight for these rifles. A rifle shooting its preferred bullet will outshine a lesser bullet pretty well across the range of charge weights. Of course, you may find the odd exception, which is more than likely a fluke.

 

[RonR]

RonR - I'm not sure that the OCW methodology works well with the average LE sporter, or off the shelf hunting rifle, for that matter. What I'm saying is that a given rifle may not "tune" well to charge weight, on a repeatable basis, to justify the time and expense.
Accordingly, once I've found my preferred bullet weight, I may go up a grain to see the effect, but that's about it. I don't push 303's to max load (easier on barrel and brass, and too many years in engineering school learning about metal failures).

To answer your question directly. If a given rifle prefers FB 174 gr Hornady's, the it will likely shoot 180 gr FB Sierra's well.. All bets are off if you go to boat-tails, or slightly undersize bullets (eg 3105 in dia..)

In closing, I guess what I'm trying to say is that charge weight tends to be a "least" variable, compared to bullet weight for these rifles. A rifle shooting its preferred bullet will outshine a lesser bullet pretty well across the range of charge weights. Of course, you may find the odd exception, which is more than likely a fluke.

Got it. Thanks for additional post and for the clarity.

Regards
Ronr