Bullet type vs powder?

[Guest kj4gxu]

I am working up a reloading setup right now and have a question.

 

Does bullet type have a significant effect on required powder charge.

For example can you use the same powder charge for a 125gr JHP bullet as is specified for a 125gr FMJ or LCN.

The reason I ask is that I see that MidSouthShooters supply has both bullets and powder in stock which is great since they're not far from me and they allow local pickup so i save shipping (and hazmat on the powder I believe).

 

however, when looking up the load data for the powders they have in stock they have a listing for a 125gr lcn bullet but the bullets that matches an in-stock powder, but the in-stock bullets are 125gr JHP.  

 

I'm expecting a Lee Loader to be delivered by UPS on Monday which will at least allow me to tinker around while I work on getting a press so I'm trying to pull together components over the next few days to work with.

I do plan on getting a press, but for now the Lee Loader is what was immediately available.  I had a press on order from Palmetto State Armory that they allegedly had "In stock" until it came time to ship, then it was back ordered.

Edited March 1, 2013 by kj4gxu

[battleop]

I came here to post a similar question and instead of starting another thread I'm going to piggy back on your question which is pretty similar.

 

Let's say I have a Berger Bullet that's 60gr and I am using 23.5grn of benchmark behind it that I know is a tack driving load that was worked up from a reloading manual. Since things are hard to find let's say I can't find the 60gr Berger but I can find a 60gr Hornady.  My load data for the Berger comes from a reloading manual that lists the Berger but it does not list the Hornady.  For the sake of safety to me and my gun (not accuracy) is it OK to start with the same load (my example is between the starting and max load) as the Berger since the Berger and the Hornady have the same weight?

 

For the sake of my example the above bullet weight and charge weights are completely made up off the top of my head and they do not represent an actual load which is why I didn't mention the caliber.

[Guest kj4gxu]

Welcome to the conversation.  One thing I did notice while looking at the Hogdon load data is that it lists only bullet type and weight, it doesn't list bullet brand.  While I can't say that would carry over to the powder brand you're using it would seem to indicate that brand is less important.  It will be interesting to see what some of the more experienced members have to say on that.

Thanks

eric

[atlas3025]

If the bullet type is similar (IE BTHP or Spitzer) I would back off the recommended load 5-10% and work up looking for pressure signs.  Basically, the more of the bullet that touches the barrel, the higher your pressure is going to be with a given charge.  If you are staying with the same bullet weight, the potential danger would be if you are using load data for a "low drag" bullet but actually loading with a "high drag" bullet such as a round nose or dangerous game bullet.

 

If you are going with load data for a high drag bullet but using a low drag bullet, you are probably OK. 

 

So to recap, if the bullet style is a blunt with long straight sides, it is going to generate more pressure than pointy bullet that is tapered. 

 

But backing the charge off 10% in either case and working should be safe, given the same bullet weights.

[Dave Shooter]

Short answer to original question --yes, type of bullet makes a difference. 

 

Gilding metal versus copper jacket versus plated versus lead all have differing coeffiecients of friction.  Different styles of the same weight may have different amounts of bearing surface.

 

How much difference?  If you're shooting mid-range pistol loads and go from one brand of jacketed bullet to another of same weight it might not be enough to worry about if all you need is for it to go bang.

 

Rifle can definetly go from safe to overpressure just by switching bullets.  The "lead free" bullets are usually longer than lead core of same weight and take up more powder space.

 

The standard advice still applies: when switching any component back off the powder and work up again.

 

Good Luck!

[ttocswob]

IMO, YMMV, (what they said, while I was typing)

 

Generally, a starting load should be safe for bullets of the same weight and type. Always start light and work up when changing components.

 

In terms of maximum charge, jacketed > plated > lead.

 

Some HP's such as XTP or Golden Saber will seat deeper into the case than typical JHP's, resulting in reduced case capacity; hence a reduced charge is required.

[Guest Fruit jar]

For some reason I can't copy and paste in this forum.

Search powderburnratechart , it give the listing of the hottest to coldest powders. If your charge shows Titegroup, but you have Bulleye, I would start with the same charge since they are next to each other. If a manual is produced by a bullet company, all the info will be with their bullets. Some bullet companies pay the powder companies to use their bullets on their charts. If a powder company manual, they only list their powders. Pretty much if it's the same size and style bullet your good to go. If for target shoots, I would go with cast. Depending on where you buy them and the amount per order they can run from $35, per 1,000 to $50 per 500 plus shipping.

[Dave Shooter]

From the Western Powders burn rate chart:

 

"Burn rate charts can never reflect the differences between powders in the correct proportion, and can only place powders in approximate burn rate envelopes.

NEVER USE THESE TO DETERMINE/CALCULATE LOADS - ALWAYS REFER TO REPUTABLE LOAD GUIDES/MANUALS."

[gregintenn]

The more difficult a bullet is to push down the bore, the LESS powder needed to push it. It sounds counterintuitive, but more resistance=a chance to build more pressure with less powder burning.

[Dolomite_supafly]

For some reason I can't copy and paste in this forum.

Search powderburnratechart , it give the listing of the hottest to coldest powders. If your charge shows Titegroup, but you have Bulleye, I would start with the same charge since they are next to each other. If a manual is produced by a bullet company, all the info will be with their bullets. Some bullet companies pay the powder companies to use their bullets on their charts. If a powder company manual, they only list their powders. Pretty much if it's the same size and style bullet your good to go. If for target shoots, I would go with cast. Depending on where you buy them and the amount per order they can run from $35, per 1,000 to $50 per 500 plus shipping.

 

 

Do not do this. Never use load data for one powder when using a different powder no matter where the fall in the chart.

 

The powders in the chart are not equally spaced. Just because two powders are next to each other does not mean that they are similar. It just means they are closer to each other than the rest of the powders. There could be huge differences between two powders that are next to each other and those differences could result in injury or death.

 

Find data for the powder you are using. There is plenty of resources for using Bullseye so there is no reason to use any other data.

 

Bearing surface and case capacity both have affects on pressure. Heavier bullets tend to have longer bearing surfaces as well as seat deeper in the cases and these increase pressures. This is why heavier bulelts tend to have a smaller charge compared to lighter bullets. Seating depth affects case capacity and pressures. You can blow a gun up using the minimum charge if you seat a bullet deep enough. This is why they ALWAYS list the OAL of the loaded cartridge.

 

Dolomite

[Dolomite_supafly]

Additionally, the powder chart does not list hottest to coldest. It list fastest to slowest. And the fastest vs slowest isn't so much about how fast the powder burns but more about how quickly the pressures subside.

 

According to Hornady all powders reach reach their max pressure very shortly, generally under an inch, but fast powders dissipate that pressure quicker while a slow powders take a little longer to dissipate. And because the slower powder is able to exert pressure over a longer time span it is able to have higher velocities for a given pressure than faster powders.

 

Think of it like this. You have two 55 gallon drums filled to the top. One has a faucet that is 1" OD and one has a faucet that is 12" OD. Both faucets have the same amount of pressure on them but if you open both the "faster burning" one with the 12" opening will empty all its energy quicker that the 1" opening. Both expend the same amount of energy but one does it in seconds while another does it in minutes.

 

Dolomite

[Mld3021]

This is great advice and very helpful. I've had the same question.

[Guest kj4gxu]

I've been doing a little more research on this and discovered that there is a bullet very close to what I'll be using on the Hodgdon load data at http://data.hodgdon.com/cartridge_load.asp That page lists a 125 gr SIE FMJ, which I didn't realize SIE was an abbreviation for Sierra but that appears to be the case.  i'll be using 125 gr Sierra JHPs so am I correct that the load data should be near interchangeable?

Based off that my thought is to start at 4.1gr of powder with a OAL of 1.090 and work my way up on the powder charge.

Does this sound reasonable or would the use of JHP vs FMJ actually require shortening the OAL?

At this point the only component I'm still waiting to obtain is primers, but I've actually got a couple of good leads on where I can find those.

 

I'll be using Titegroup powder with 125 gr Sierra Sports Master jhp.

Thanks again

Eric

[ttocswob]

Not familiar with the Sierra JHP - but generally a starting load should be similar for both FMJ and standard JHP's of the same mass.

 

Where you could get in trouble is not OAL, but seating depth - with XTP's Gold Dots, or Golden Saber, the missing mass from the large cavity hollow point is made up with more lead in the base of the bullet. The same OAL can result in less case capacity and necessitate a reduced charge. Again I don't know if the Sierra is affected by this.

 

Also depends on caliber - a .38 special has plenty of case capacity, while a 9mm is much smaller. Seating depth is much less likely to be a problem in the larger .38 Special.

 

YMMV, yada

[Jonnin]

I've been doing a little more research on this and discovered that there is a bullet very close to what I'll be using on the Hodgdon load data at http://data.hodgdon.com/cartridge_load.asp That page lists a 125 gr SIE FMJ, which I didn't realize SIE was an abbreviation for Sierra but that appears to be the case.  i'll be using 125 gr Sierra JHPs so am I correct that the load data should be near interchangeable?

Based off that my thought is to start at 4.1gr of powder with a OAL of 1.090 and work my way up on the powder charge.

Does this sound reasonable or would the use of JHP vs FMJ actually require shortening the OAL?

At this point the only component I'm still waiting to obtain is primers, but I've actually got a couple of good leads on where I can find those.

 

I'll be using Titegroup powder with 125 gr Sierra Sports Master jhp.

Thanks again

Eric

 

9mm builds pressure very fast as you seat the bullet deeper.  If you seat to the same depth, you can use the same charge for the same material of bullet.  For example a 115 grain copper JHP and a 115 grain FMJ seated the same depth can share the same charge.  Depth is not related to OAL directly however, and that is the catch!  If you are using a powder charge for a similar but different bullet, what you said is exactly what to do: start with a very light charge and work it up slowly and carefully.  

 

All that to say it will likely be close.  That is, it is *very* likely that a working load for a JHP exists between the min/max loads for a FMJ of the same material and weight; they absolutely should overlap unless using the hottest powder you can find where .25 grain is the difference between max/min or something crazy like that.   Which means you can do as you are doing, pick the closest match in the load data to what you have, back off for safety, and go from there.

[Guest kj4gxu]

Thanks Jonnin and ttocswob;

 

Based on your replies I'll go with the plan I had starting at the bottom of the load data or even a couple tenths of a gr below it and work up from there with the OAL 1.090.  I made up a couple dummies last night at that length and they seemed to feed through just fine when manually cycling the slide.

 

Thanks again

Eric